Journal articles on the topic 'Enzyme Inhibition Potency'
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1
Yamali, Cem, Halise Inci Gul, Tahir Cakir, Yeliz Demir, and Ilhami Gulcin. "Aminoalkylated Phenolic Chalcones: Investigation of Biological Effects on Acetylcholinesterase and Carbonic Anhydrase I and II as Potential Lead Enzyme Inhibitors." Letters in Drug Design & Discovery 17, no. 10 (October 12, 2020): 1283–92. http://dx.doi.org/10.2174/1570180817999200520123510.
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Background: Phenolic Mannich bases have been reported as acetylcholinesterase (AChE) inhibitors for the medication of Alzheimer's disease. Carbonic Anhydrases (CAs) are molecular targets for anticonvulsant, diuretic and antiglaucoma drugs in the clinic. Phenolic compounds have also been mentioned as CA inhibitors. The importance of Mannich bases in drug design inspired our research group to design novel phenolic Mannic bases as potent enzyme inhibitors. Objective: In this study, novel Mannich bases, 1-(3,5-bis-aminomethyl-4-hydroxyphenyl)-3-(4- substitutedphenyl)-2-propen-1-ones (1-9), were designed to discover new and potent AChE inhibitors for the treatment of Alzheimer's disease and also to report their carbonic anhydrase inhibitory potency against the most studied hCA I and hCA II isoenzymes with the hope to find out promising enzyme inhibitors. Methods: Mannich bases were synthesized by the Mannich reaction. The structures of the compounds were elucidated by 1H NMR, 13C NMR, and HRMS. Enzyme inhibitory potency of the compounds was evaluated spectrophotometrically towards AChE, hCA I and hCA II enzymes. Results and Discussion: The compounds showed inhibition potency in nanomolar concentrations against AChE with Ki values ranging from 20.44±3.17 nM to 43.25±6.28 nM. They also showed CAs inhibition potency with Ki values in the range of 11.76±1.29-31.09±2.7 nM (hCA I) and 6.08 ± 1.18-23.12±4.26 nM (hCA II). Compounds 1 (hCA I), 5 (hCA II), and 4 (AChE) showed significant inhibitory potency against the enzymes targeted. Conclusion: Enzyme assays showed that Mannich derivatives might be considered as lead enzyme inhibitors to design more selective and potent compounds targeting enzyme-based diseases.
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Giresha, Aladahalli S., Deepadarshan Urs, Sophiya Pundalik, Rajkumar S. Meti, Siddanakoppalu N. Pramod, Ballenahalli H. Supreetha, Madhusudana Somegowda, et al. "Sinapicacid Inhibits Group IIA Secretory Phospholipase A2 and Its Inflammatory Response in Mice." Antioxidants 11, no. 7 (June 25, 2022): 1251. http://dx.doi.org/10.3390/antiox11071251.
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Human Group IIA secreted phospholipase A2 (sPLA2-IIA) enzyme plays a crucial role in several chronic inflammatory diseases such asasthma, atherosclerosis, gout, bronchitis, etc. Several studies showed that the antioxidants exert an anti-inflammatory function by inhibiting the sPLA2-IIA enzyme. Hence, the present study evaluated an antioxidant molecule, sinapic acid, for sPLA2-IIA inhibition as an anti-inflammatory function. Initially, the antioxidant efficacy of sinapic acid was evaluated, and it showed greater antioxidant potency. Further, sinapic acid inhibited 94.4 ± 4.83% of sPLA2-IIA activity with an IC50 value of 4.16 ± 0.13 µM. The mode of sPLA2-IIA inhibition was examined by increasing the substrate concentration from 30 to 120nM and the calcium concentration from 2.5 to 15 mM, which did not change the level of inhibition. Further, sinapic acid altered the intrinsic fluorescence and distorted the far UltraViolet Circular Dichroism (UV-CD) spectra of the sPLA2-IIA, indicating the direct enzyme-inhibitor interaction. Sinapic acid reduced the sPLA2-IIA mediated hemolytic activity from 94 ± 2.19% to 12.35 ± 2.57% and mouse paw edema from 171.75 ± 2.2% to 114.8 ± 1.98%, demonstrating the anti-inflammatory efficiency of sinapic acid by in situ and in vivo methods, respectively. Finally, sinapic acid reduced the hemorrhagic effect of Vipera russelli venom hemorrhagic complex-I (VR-HC-I) as an anti-hemorrhagic function. Thus, the above experimental results revealed the sinapic acid potency to be an antioxidant, anti-inflammatory and anti-hemorrhagic molecule, and therefore, it appears to be a promising therapeutic agent.
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Martyn, Derek C., Michael J. B. Moore, and Andrew D. Abell. "Succinimide and Saccharin-based Enzyme-activated Inhibitors of Serine Proteases." Current Pharmaceutical Design 5, no. 6 (June 1999): 405–15. http://dx.doi.org/10.2174/138161280505230110110545.
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Abstract: The inhibition of human leukocyte elastase (HLE). and other serine proteases, by succinimide and saccharin-based compounds is reviewed. The succinimide compounds are unique in that the inactivating species is generated within the enzyme active site via a molecular rearrangement. The related saccharin derivatives also inactivate serine proteases by an enzyme-activated mechanism. Those factors effecting the potency, selectivity and stability of these important classes of inhibitor are discussed.
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Liu, Liqin, Violeta Yu, Jeanne Pistillo, Josie Lee, Laurie B. Schenkel, Stephanie Geuns-Meyer, Ivonne Archibeque, Angus Sinclair, Renee Emkey, and Graham Molineux. "New Insights on Assessing Intra-Family Selectivity for Jak2 Inhibitors." Blood 118, no. 21 (November 18, 2011): 5150. http://dx.doi.org/10.1182/blood.v118.21.5150.5150.
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Abstract Abstract 5150 Essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF) are myeloproliferative disorders (MPDs) characterized by a chronic over-production of cells of one or more blood cell lineages and/or bone marrow fibrosis which may, on occasion, progress to acute myeloid leukemia. The V617F gain of function mutation in the pseudokinase domain of Jak2, which results in constitutive activation of Jak2, is the most frequent mutation associated with MPD. Constitutively activated Jak2 can lead to dysregulated downstream signaling pathways (STAT, MAP kinase, and PI3 kinase) which in turn trigger abnormal growth, survival and differentiation of hematopoietic progenitors. Therefore, inhibition of constitutively activated Jak2 may offer therapeutic potential. Designing a Jak2V617F specific inhibitor encounters challenges due to the lack of enzymatic activity of the pseudokinase domain of Jak2. In lieu of a Jak2V617F mutant selective inhibitor, a highly selective inhibitor of Jak2 is likely an attainable goal. Jak2 is a member of the Jak family of kinases including Jak1, Jak3, and Tyk2. Highly selective Jak2 inhibitors may provide a better safety margin in chronic dosing settings in ET and PV patients since inhibiting other Jak family members could cause side-effects such as immunosuppression. Attaining the desired selectivity of Jak2 inhibition versus the other family members has been challenging and few compounds have been reported to date that have the desired Jak2 selectivity. This can be attributed to the high homology of the ATP binding pocket among Jak family members, but is also hampered by a lack of assays capable of distinguishing the Jak-selectivity profile in a physiologically relevant setting. We compared the potency and selectivity of compounds tested in a pSTAT5 AlphaScreen® assay panel consisting of isogenic Ba/F3 cell lines individually expressing translocated ETS leukemia (TEL) fusions of each Jak-family member (Ba/F3-TEL-Jak) with data from corresponding Jak enzyme assays. Here we report that the selectivity of inhibitor compounds illustrated in enzyme assays did not correlate with the selectivity profile in cell lines due to different shifts in potency for each family member between enzyme and cells (Figure 1). As a consequence the selectivity of compounds for Jak2 against Jak1 observed in enzyme assays may be reduced or reversed in cellular assays. On the other hand, Jak2 selectivity over Jak3 seen in the enzyme assays was conserved in the cellular assay. Thus, we propose that compounds that exhibit greater potency on Jak2 compared to Jak1 in the enzyme assays are needed and should be the main focus of medicinal chemistry efforts in order to attain Jak2 selectivity over Jak1 in a cellular context. We also compared the potency and selectivity of compounds in the isogenic Ba/F3-TEL-Jak cell lines with data obtained with cytokine stimulated peripheral blood mononuclear cells (PBMCs). The potency and selectivity of compounds in PBMCs are determined by measuring the inhibition of phosphorylation of STAT5 in TPO or GM-CSF stimulated platelets or monocytes (mediated by Jak2) and in IL-2 stimulated lymphocytes (mediated by Jak1 and Jak3). We found that potency correlated well between PBMCs and Ba/F3-TEL-Jak2 cells, and the rank order of compounds based on IC50 values obtained with Ba/F3-TEL-Jak cell lines were conserved well in PBMCs; the compound selectivity profiles derived from the Ba/F3-TEL-Jak cell assays were predictive of Jak2 selectivity profiles obtained in the PBMC assays. Therefore, inclusion of Ba/F3-TEL-Jak pSTAT5 cellular assays may be useful for Jak family inhibitor development. Our results also suggest that relying solely on enzyme potency and selectivity data can be misleading, and that evaluating cellular selectivity in a biologically relevant context may provide a more meaningful understanding of selectivity and lead to the development of more selective Jak2 compounds. Disclosures: Liu: Amgen, Inc: Employment. Yu:Amgen: Employment. Pistillo:Amgen: Employment. Lee:Amgen: Employment. Schenkel:Amgen: Employment. Geuns-Meyer:Amgen: Employment. Archibeque:Amgen: Employment. Sinclair:Amgen: Employment. Emkey:Amgen: Employment. Molineux:Amgen: Employment.
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Pratasik, Veronika, Revolson Mege, and Mokosuli Semuel Yermia. "In Vitro Antidiabetic Activity Of Apis dorsata Binghami Nest Extract." JURNAL PEMBELAJARAN DAN BIOLOGI NUKLEUS 8, no. 3 (November 25, 2022): 733–43. http://dx.doi.org/10.36987/jpbn.v8i3.3196.
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Indonesia is ranked 7th out of 10 countries with the highest number of people with diabetes mellitus, which is estimated to increase every year.α -amylase is an enzyme that catalyzes the hydrolysis of α-1,4 glycosidic bonds of polysaccharides to produce dextrins, oligosaccharides, maltose and D-glucose. Apis dorsata Binghami honeycomb contains secondary metabolites that have antidiabetic potential, including inhibiting the action of the α-amylase enzyme. The purpose of this study was to determine the in vitro antidiabetic potential of Apis dorsata binghami nest extract. This study uses a descriptive research method where the research data are obtained through laboratory experiments. Honeycomb extraction using maceration method. Analysis of total flavonoid content using UV-Vis spectrophotometric method. Antidiabetic potency test using -amylase enzyme inhibition method. The results of the extraction study showed that the % yield of the extract was 11.82% with a brownish yellow color. Analysis of the total flavonoid content showed the results of 3.33 mgQE/g. The inhibitory activity of the -amylase enzyme, the IC50 value of the extract obtained was 158.48±7.42 g/mL, the acarbose value was 165.96±7.08 g/mL. These results indicate that the extract of A.dorsata Binghami nest has hyperglycemic activity by inhibiting complex carbohydrate hydrolyzing enzymes such as inhibition of the -amylase enzyme which is better than acarbose because the IC50 value of the extract is smaller. If the IC50 value is smaller then the enzyme inhibition is stronger. For further research, it is recommended to use a more specific enzyme, namely the -glucosidase enzyme.
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Kern, Gunther, Tiffany Palmer, David E. Ehmann, Adam B. Shapiro, Beth Andrews, Gregory S. Basarab, Peter Doig, et al. "Inhibition of Neisseria gonorrhoeae Type II Topoisomerases by the Novel Spiropyrimidinetrione AZD0914." Journal of Biological Chemistry 290, no. 34 (July 6, 2015): 20984–94. http://dx.doi.org/10.1074/jbc.m115.663534.
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We characterized the inhibition of Neisseria gonorrhoeae type II topoisomerases gyrase and topoisomerase IV by AZD0914 (AZD0914 will be henceforth known as ETX0914 (Entasis Therapeutics)), a novel spiropyrimidinetrione antibacterial compound that is currently in clinical trials for treatment of drug-resistant gonorrhea. AZD0914 has potent bactericidal activity against N. gonorrhoeae, including multidrug-resistant strains and key Gram-positive, fastidious Gram-negative, atypical, and anaerobic bacterial species (Huband, M. D., Bradford, P. A., Otterson, L. G., Basrab, G. S., Giacobe, R. A., Patey, S. A., Kutschke, A. C., Johnstone, M. R., Potter, M. E., Miller, P. F., and Mueller, J. P. (2014) In Vitro Antibacterial Activity of AZD0914: A New Spiropyrimidinetrione DNA Gyrase/Topoisomerase Inhibitor with Potent Activity against Gram-positive, Fastidious Gram-negative, and Atypical Bacteria. Antimicrob. Agents Chemother. 59, 467–474). AZD0914 inhibited DNA biosynthesis preferentially to other macromolecules in Escherichia coli and induced the SOS response to DNA damage in E. coli. AZD0914 stabilized the enzyme-DNA cleaved complex for N. gonorrhoeae gyrase and topoisomerase IV. The potency of AZD0914 for inhibition of supercoiling and the stabilization of cleaved complex by N. gonorrhoeae gyrase increased in a fluoroquinolone-resistant mutant enzyme. When a mutation, conferring mild resistance to AZD0914, was present in the fluoroquinolone-resistant mutant, the potency of ciprofloxacin for inhibition of supercoiling and stabilization of cleaved complex was increased greater than 20-fold. In contrast to ciprofloxacin, religation of the cleaved DNA did not occur in the presence of AZD0914 upon removal of magnesium from the DNA-gyrase-inhibitor complex. AZD0914 had relatively low potency for inhibition of human type II topoisomerases α and β.
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Betari, Nibal, Kristoffer Sahlholm, Yuta Ishizuka, Knut Teigen, and Jan Haavik. "Discovery and biological characterization of a novel scaffold for potent inhibitors of peripheral serotonin synthesis." Future Medicinal Chemistry 12, no. 16 (August 2020): 1461–74. http://dx.doi.org/10.4155/fmc-2020-0127.
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Aim: Tryptophan hydroxylase 1 (TPH1) catalyzes serotonin synthesis in peripheral tissues. Selective TPH1 inhibitors may be useful for treating disorders related to serotonin dysregulation. Results & methodology: Screening using a thermal shift assay for TPH1 binders yielded Compound 1 (2-(4-methylphenyl)-1,2-benzisothiazol-3(2 H)-one), which showed high potency (50% inhibition at 98 ± 30 nM) and selectivity for inhibiting TPH over related aromatic amino acid hydroxylases in enzyme activity assays. Structure–activity relationships studies revealed several analogs of 1 showing comparable potency. Kinetic studies suggested a noncompetitive mode of action of 1, with regards to tryptophan and tetrahydrobiopterin. Computational docking studies and live cell assays were also performed. Conclusion: This TPH1 inhibitor scaffold may be useful for developing new therapeutics for treating elevated peripheral serotonin.
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OUELLET, Marc, Jean-Pierre FALGUEYRET, and M. David PERCIVAL. "Detergents profoundly affect inhibitor potencies against both cyclo-oxygenase isoforms." Biochemical Journal 377, no. 3 (February 1, 2004): 675–84. http://dx.doi.org/10.1042/bj20030969.
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The sensitivity of Coxs (cyclo-oxygenases) to inhibition is known to be highly dependent on assay conditions. In the present study, the inhibitor sensitivities of purified Cox-1 and -2 were determined in a colorimetric assay using the reducing agent N,N,N´,N´-tetramethyl-p-phenylenediamine. With the detergent genapol X-100 (2 mM) present, the potencies of nimesulide, ibuprofen, flufenamic acid, niflumic acid and naproxen were increased over 100-fold against Cox-2 and titration curve shapes changed, so that maximal inhibition now approached 100%. Indomethacin, diclofenac and flosulide were not changed in potency. Similar effects of genapol were observed with inhibitors of Cox-1. DuP-697 and two analogues became more than 10-fold less potent against Cox-2 with genapol present. Tween-20, Triton X-100 and phosphatidylcholine, but not octylglucoside, gave qualitatively similar effects as genapol. Similar detergent-dependent changes in inhibitor potency were also observed using a [14C]arachidonic acid HPLC assay. The increases in potency of ibuprofen, flufenamic acid, isoxicam and niflumic acid towards Cox-2 and ibuprofen towards Cox-1 were accompanied by a change from time-independent to time-dependent inhibition. The interactions of Cox inhibitors has been described in terms of multiple binding step mechanisms. The genapol-dependent increase in inhibitor potency for ketoprofen was associated with an increase in the rate constant for the conversion of the initial enzyme–inhibitor complex to a second, more tightly bound form. The loss of potency for some inhibitors is probably due to inhibitor partitioning into detergent micelles. The present study identifies detergents as another factor that must be considered when determining inhibitor potencies against both Cox isoforms.
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Davies, Gareth, Hannah Semple, Megan McCandless, Jonathan Cairns, and Geoffrey A. Holdgate. "High-Throughput Mechanism of Inhibition." SLAS DISCOVERY: Advancing the Science of Drug Discovery 26, no. 2 (January 22, 2021): 248–56. http://dx.doi.org/10.1177/2472555220983809.
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Enzymes represent a significant proportion of the druggable genome and constitute a rich source of drug targets. Delivery of a successful program for developing a modulator of enzyme activity requires an understanding of the enzyme’s mechanism and the mode of interaction of compounds. This allows an understanding of how physiological conditions in disease-relevant cells will affect inhibitor potency. As a result, there is increasing interest in evaluating hit compounds from high-throughput screens to determine their mode of interaction with the target. This work revisits the common inhibition modalities and illustrates the impact of substrate concentration relative to Km upon the pattern of changes in IC50 that are expected for increasing substrate concentration. It proposes a new, high-throughput approach for assessing mode of inhibition, incorporating analyses based on a minimal descriptive model, to deliver a workflow that allows rapid and earlier compound classification immediately after high-throughput screening.
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Haehner, Thomas, Ulrich Massing, Torsten Diesinger, and Dieter Müller-Enoch. "Inhibition of Cytochrome P450 Mediated Enzyme Activity by Alkylphosphocholines." Zeitschrift für Naturforschung C 59, no. 7-8 (August 1, 2004): 599–605. http://dx.doi.org/10.1515/znc-2004-7-826.
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AbstractThe inhibitory potency of four alkylphospholipids: rac-1-O-phosphocholine-2-hydroxy-octadecane (rac-2-OH), rac-1-O-phosphocholine-2-O-acetyl-octadecane (rac-2-O-acetyl), rac-1- O-phosphocholine-2-amino-octadecane (rac-2-NH2) and rac-1-O-phosphocholine-2-N-acetyloctadecane (rac-2-N-acetyl), on the cytochrome P450-dependent monooxygenase activity has been evaluated. The IC50 values of the alkylphosphocholines with 7-ethoxycoumarin as substrate in liver microsomal fractions of PB-treated rats and with a reconstituted CYP2B1: NADPH-P450-reductase system are in the range of 3.2D5.0 μм and 2.8D3.5 μм, respectively. Lineweaver-Burk plots with the inhibitors in concentrations that were found to cause roughly a 50% inhibition and with 7-ethoxycoumarin as substrate revealed for all four alkylphospholipids a competitive inhibition type. The degree of the competitive inhibition is quantified by the Ki values. With liver microsomal fractions of PB-treated rats, the Ki values of rac-2-OH (Ki = 1.36 μм) and rac-2-O-acetyl (Ki = 1.33 μm) differs slightly from those of rac-2-NH2 (Ki = 2.2 μм) and rac-2-N-acetyl (Ki = 2.2 μм), but with the reconstituted CYP2B1: NADPHP450- reductase system all Ki values are in the small range of 1.8 D 2.6 μм, indicating that the short substituted group at the 2-position (OH; O-acetyl; NH2; N-acetyl) of the long chain octadecanol part of the phosphodiesters exhibit no essential role on the strong inhibitory potency of these alkylphosphocholines on the 7-ethoxycoumarin-O-deethylase activity.
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Hulcová, Daniela, Kateřina Breiterová, Lucie Zemanová, Tomáš Siatka, Marcela Šafratová, Nina Vaněčková, Anna Hošťálková, Vladimír Wsól, and Lucie Cahlíková. "AKR1C3 Inhibitory Potency of Naturally-occurring Amaryllidaceae Alkaloids of Different Structural Types." Natural Product Communications 12, no. 2 (February 2017): 1934578X1701200. http://dx.doi.org/10.1177/1934578x1701200226.
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Aldo-keto reductase 1C3 (AKR1C3) is an important human enzyme that participates in the reduction of steroids and prostaglandins, which leads to proliferative signaling. AKR1C3 is frequently upregulated in various cancers, and this enzyme has been suggested as a therapeutic target for the treatment of these pathological conditions. The fact that the isoquinoline alkaloid stylopine has been identified as a potent AKR1C3 inhibitor has prompted us to screen a library of diverse types of Amaryllidaceae alkaloids, which biogenetically are isoquinoline alkaloids, on a recombinant form of AKR1C3. From the tested compounds, only tazettine showed moderate AKR1C3 inhibitory potency with an IC50 value of 15.8 ± 1.2 μM. Tazettine is a common Amaryllidaceae alkaloid, which could be used as a model substance for the further development of either analogues or related compounds with better inhibition potency.
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Sari, Desi Ratna, Aurelia Afra, Erni Yupita Sari Br Sembiring, and Cico Jhon Karunia Simamora. "Fat-Rich Food Review on Obesity Control through Induction Enzyme Inhibitors." BIOEDUSCIENCE 5, no. 3 (December 31, 2021): 211–17. http://dx.doi.org/10.22236/j.bes/536903.
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Background: Obesity is an imbalance between height and weight due to excessive body fat tissue. The purpose of writing this review is to find out the effect of enzyme inhibitor induction on fat-rich foods as control of obesity. Method: Writing and assessing source problems related to using literature study methods. Results: One way of controlling obesity is by regulating dietary patterns and consumption of lipase inhibitors. Inhibition of lipase is one of the most widely developed effective ways in diet medicine. Inhibitory compounds cause pancreatic lipase to lose its ability in decomposition that enters the blood. The potency of plant-origin lipase inhibitor compounds can be increased in both number and performance. Increasing the production of secondary metabolite group inhibitors is by fermentation of microorganisms. Conclusion: Inhibition of triglyceride hydrolysis through inhibition of lipase enzymes can decrease and prevent obesity. Secondary metabolite induction can be fermented with microorganisms. The production of secondary metabolite compounds in medicinal plants can be increased in the presence of fermentation. Flavonoids can decrease the accumulation of lipids in the heart, reduce glucose absorption, inhibit the breakdown of polysaccharides into monosaccharides.
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Prasa, D., L. Svendsen, and J. Stürzebecher. "Inhibition of Thrombin Generation in Plasma by Inhibitors of Factor Xa." Thrombosis and Haemostasis 78, no. 04 (1997): 1215–20. http://dx.doi.org/10.1055/s-0038-1657717.
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SummaryA series of inhibitors of factor Xa (FXa) were investigated using the thrombin generation assay to evaluate the potency and specificity needed to efficiently block thrombin generation in activated human plasma. By inhibiting FXa the generation of thrombin in plasma is delayed and decreased. Inhibitor concentrations which cause 50 percent inhibition of thrombin generation (IC50) correlate in principle with the Ki values for inhibition of free FXa. Recombinant tick anticoagulant peptide (r-TAP) is able to inhibit thrombin generation with considerably low IC50 values of 49 nM and 37 nM for extrinsic and intrinsic activation, respectively. However, the potent synthetic, low molecular weight inhibitors of FXa (Ki values of about 20 nM) are less effective in inhibiting the generation of thrombin with IC50 values at micromolar concentrations.The overall effect of inhibitors of FXa in the thrombin generation assay was compared to that of thrombin inhibitors. On the basis of similar Ki values for the inhibition of the respective enzyme, synthetic FXa inhibitors are less effective than thrombin inhibitors. In contrast, the highly potent FXa inhibitor r-TAP causes a stronger reduction of the thrombin activity in plasma than the most potent thrombin inhibitor hirudin.
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Aragaw, Wassihun Wedajo, Brendon M. Lee, Xuan Yang, Matthew D. Zimmerman, Martin Gengenbacher, Véronique Dartois, Wai-Keung Chui, Colin J. Jackson, and Thomas Dick. "Potency boost of a Mycobacterium tuberculosis dihydrofolate reductase inhibitor by multienzyme F420H2-dependent reduction." Proceedings of the National Academy of Sciences 118, no. 25 (June 14, 2021): e2025172118. http://dx.doi.org/10.1073/pnas.2025172118.
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Triaza-coumarin (TA-C) is a Mycobacterium tuberculosis (Mtb) dihydrofolate reductase (DHFR) inhibitor with an IC50 (half maximal inhibitory concentration) of ∼1 µM against the enzyme. Despite this moderate target inhibition, TA-C shows exquisite antimycobacterial activity (MIC50, concentration inhibiting growth by 50% = 10 to 20 nM). Here, we investigated the mechanism underlying this potency disconnect. To confirm that TA-C targets DHFR and investigate its unusual potency pattern, we focused on resistance mechanisms. In Mtb, resistance to DHFR inhibitors is frequently associated with mutations in thymidylate synthase thyA, which sensitizes Mtb to DHFR inhibition, rather than in DHFR itself. We observed thyA mutations, consistent with TA-C interfering with the folate pathway. A second resistance mechanism involved biosynthesis of the redox coenzyme F420. Thus, we hypothesized that TA-C may be metabolized by Mtb F420–dependent oxidoreductases (FDORs). By chemically blocking the putative site of FDOR-mediated reduction in TA-C, we reproduced the F420-dependent resistance phenotype, suggesting that F420H2-dependent reduction is required for TA-C to exert its potent antibacterial activity. Indeed, chemically synthesized TA-C-Acid, the putative product of TA-C reduction, displayed a 100-fold lower IC50 against DHFR. Screening seven recombinant Mtb FDORs revealed that at least two of these enzymes reduce TA-C. This redundancy in activation explains why no mutations in the activating enzymes were identified in the resistance screen. Analysis of the reaction products confirmed that FDORs reduce TA-C at the predicted site, yielding TA-C-Acid. This work demonstrates that intrabacterial metabolism converts TA-C, a moderately active “prodrug,” into a 100-fold-more-potent DHFR inhibitor, thus explaining the disconnect between enzymatic and whole-cell activity.
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Hasinoff, B. B., and J. P. Davey. "The inhibition of a membrane-bound enzyme as a model for anaesthetic action and drug toxicity." Biochemical Journal 258, no. 1 (February 15, 1989): 101–7. http://dx.doi.org/10.1042/bj2580101.
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The inhibition of the membrane-bound enzyme cytochrome c oxidase by aliphatic n-alcohols and other neutral organic compounds was studied as a model for anaesthetic action and drug toxicity. The n-alcohols (C1 to C14) displayed a variation in inhibition constant of over 500,000-fold. The inhibition constants correlated well with the number of carbon atoms in the n-alcohols and also their n-octanol/water partition coefficients. General anaesthetic potency is known to be similarly well correlated with octanol/water partition coefficients. The free-energy change for transferring a methylene group of the n-alcohol to the more hydrophobic environment bound to the enzyme is similar to that for transferring a methylene group from water to pure alcohol. These results are consistent with the n-alcohols inhibiting by binding to an octanol-like environment on the enzyme or the protein/phospholipid interface. Neither negatively charged carboxylates nor positively charged amine analogues were observed to cause any inhibition, indicating that this postulated binding site may be uncharged. Inhibition of cytochrome c oxidase by n-alcohols was also demonstrated in both bovine heart and rat liver sonicated submitochondrial fragments.
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Ojo, Kayode K., J. Robert Gillespie, Aaron J. Riechers, Alberto J. Napuli, Christophe L. M. J. Verlinde, Frederick S. Buckner, Michael H. Gelb, et al. "Glycogen Synthase Kinase 3 Is a Potential Drug Target for African Trypanosomiasis Therapy." Antimicrobial Agents and Chemotherapy 52, no. 10 (July 21, 2008): 3710–17. http://dx.doi.org/10.1128/aac.00364-08.
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ABSTRACT Development of a safe, effective, and inexpensive therapy for African trypanosomiasis is an urgent priority. In this study, we evaluated the validity of Trypanosoma brucei glycogen synthase kinase 3 (GSK-3) as a potential drug target. Interference with the RNA of either of two GSK-3 homologues in bloodstream-form T. brucei parasites led to growth arrest and altered parasite morphology, demonstrating their requirement for cell survival. Since the growth arrest after RNA interference appeared to be more profound for T. brucei GSK-3 “short” (Tb10.161.3140) than for T. brucei GSK-3 “long” (Tb927.7.2420), we focused on T. brucei GSK-3 short for further studies. T. brucei GSK-3 short with an N-terminal maltose-binding protein fusion was cloned, expressed, and purified in a functional form. The potency of a GSK-3-focused inhibitor library against the recombinant enzyme of T. brucei GSK-3 short, as well as bloodstream-form parasites, was evaluated with the aim of determining if compounds that inhibit enzyme activity could also block the parasites' growth and proliferation. Among the compounds active against the cell, there was an excellent correlation between activity inhibiting the T. brucei GSK-3 short enzyme and the inhibition of T. brucei growth. Thus, there is reasonable genetic and chemical validation of GSK-3 short as a drug target for T. brucei. Finally, selective inhibition may be required for therapy targeting the GSK-3 enzyme, and a molecular model of the T. brucei GSK-3 short enzyme suggests that compounds that selectively inhibit T. brucei GSK-3 short over the human GSK-3 enzymes can be found.
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Hara, A., M. Shinoda, T. Kanazu, T. Nakayama, Y. Deyashiki, and H. Sawada. "Inhibition of dimeric dihydrodiol dehydrogenases of rabbit and pig lens by ascorbic acid." Biochemical Journal 275, no. 1 (April 1, 1991): 121–26. http://dx.doi.org/10.1042/bj2750121.
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The dehydrogenase activity of dimeric dihydrodiol dehydrogenases (DD) purified from pig and rabbit lenses was inhibited by either L-ascorbic acid or its epimer, isoascorbic acid, at pH 7.5. Isoascorbate [IC50 (concn. giving 50% inhibition) = 0.043 mM for the pig enzyme; IC50 = 0.13 mM for the rabbit enzyme] was a more potent inhibitor than ascorbate (IC50 values 0.45 and 0.90 mM respectively), but 1 mM-dehydroascorbate gave less than 30% inhibition. Glucose, glucuronate, gulono-gamma-lactone, glutathione and dithiothreitol did not inhibit the enzyme activity. The inhibition by isoascorbate and ascorbate was instantaneous and reversible, and their inhibitory potency was decreased by addition of ascorbate oxidase. In the reverse reaction, isoascorbate and ascorbate gave low IC50 values of 0.013 and 0.10 mM respectively for the pig enzyme and 0.025 and 0.25 mM for the rabbit enzyme. The inhibition patterns by the two compounds were competitive with respect to dihydrodiols of naphthalene and benzene and uncompetitive with respect to NADP+, but those in the reverse reaction were uncompetitive with respect to both carbonyl substrate and NADPH. The steady-state kinetic measurements in the forward and reverse reactions by the pig enzyme were consistent with an ordered Bi Bi mechanism, in which NADP+ binds to the enzyme first and NADPH leaves last. The results indicate that ascorbate and its epimer directly bind to an enzyme: NADP+ binary complex as dead-end inhibitors. Thus ascorbate may be an important modulator of DD in the lens.
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Rožman, Kaja, Evan M. Alexander, Eva Ogorevc, Krištof Bozovičar, Izidor Sosič, Courtney C. Aldrich, and Stanislav Gobec. "Psoralen Derivatives as Inhibitors of Mycobacterium tuberculosis Proteasome." Molecules 25, no. 6 (March 12, 2020): 1305. http://dx.doi.org/10.3390/molecules25061305.
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Protein degradation is a fundamental process in all living organisms. An important part of this system is a multisubunit, barrel-shaped protease complex called the proteasome. This enzyme is directly responsible for the proteolysis of ubiquitin- or pup-tagged proteins to smaller peptides. In this study, we present a series of 92 psoralen derivatives, of which 15 displayed inhibitory potency against the Mycobacterium tuberculosis proteasome in low micromolar concentrations. The best inhibitors, i.e., 8, 11, 13 and 15, exhibited a mixed type of inhibition and overall good inhibitory potency in biochemical assays. N-(cyanomethyl)acetamide 8 (Ki = 5.6 µM) and carboxaldehyde-based derivative 15 (Ki = 14.9 µM) were shown to be reversible inhibitors of the enzyme. On the other hand, pyrrolidine-2,5-dione esters 11 and 13 irreversibly inhibited the enzyme with Ki values of 4.2 µM and 1.1 µM, respectively. In addition, we showed that an established immunoproteasome inhibitor, PR-957, is a noncompetitive irreversible inhibitor of the mycobacterial proteasome (Ki = 5.2 ± 1.9 µM, kinact/Ki = 96 ± 41 M−1·s−1). These compounds represent interesting hit compounds for further optimization in the development of new drugs for the treatment of tuberculosis.
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Baruah, Prayasee, Mostofa Ataur Rohman, Semen O. Yesylevskyy, and Sivaprasad Mitra. "Therapeutic potency of substituted chromones as Alzheimer’s drug: Elucidation of acetylcholinesterase inhibitory activity through spectroscopic and molecular modelling investigation." BioImpacts 9, no. 2 (March 8, 2019): 79–88. http://dx.doi.org/10.15171/bi.2019.11.
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Introduction: Documentation on the potency of chromones as acetylcholinesterase (AChE) antagonists has paved the way for the design and usage of new chromone analogues as inhibitors of AChE modelled on the hypothesis based on cholinergic pathway of Alzheimer’s disease (AD). Here, 2 minimally substituted chromones, namely 3-cyanochromone (CyC) and 7-amino-3-methylchromone (AMC), were checked for their AChE inhibition efficacies and plasma protein modulation. Methods: Colorimetric enzymatic assay as well as fluorescence measurements were performed for obtaining the experimental results, which were further corroborated by molecular docking and simulation studies. Results: The investigated systems exhibited strong inhibition activities against AChE, with CyC (IC50= 85.12 ± 6.70 nM) acting as better inhibitor than AMC (IC50 = 103.09 ± 11.90 nM) and both having IC50 values in the range of FDA approved cholinergic drug Donepezil (IC50 = 74.13 ± 8.30 nM). Non-competitive inhibition was observed in both the cases with the inhibitors binding near the peripheral anionic site (PAS) of the enzyme. Having one planar nitrile group in CyC as compared to sp3 hybridised substituents in AMC facilitated stacking interactions in the former, accounting for its higher inhibitory efficacy. A significant decrease in the inhibition potency of CyC (~32%) was noted in comparison with AMC (~5%) when the experiments were performed in presence of human serum albumin (HSA) instead of pure aqueous buffer. Conclusion: This comparative study affirms the importance of meticulous substitution in the chromone scaffold to promote maximum inhibition potency, while considering their usage as AD drugs.
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Connor, M. J., and M. H. Smit. "Terminal-group oxidation of retinol by mouse epidermis. Inhibition in vitro and in vivo." Biochemical Journal 244, no. 2 (June 1, 1987): 489–92. http://dx.doi.org/10.1042/bj2440489.
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Locally applied retinol is metabolized to retinoic acid in mouse epidermis in vivo. To characterize the oxidation system we investigated the ability of soluble extracts of hairless-mouse epidermis to convert retinol and retinal into retinoic acid. The extracts oxidized retinol to retinoic acid in two steps catalysed by two NAD+-dependent enzymes that were resolved on h.p.l.c. The first enzyme catalyses the reversible oxidation of retinol to retinal and is an alcohol dehydrogenase isoenzyme. The second enzyme oxidizes retinal to retinoic acid. Retinol oxidation by epidermal extracts was inhibited by the alcohol dehydrogenase inhibitor 4-methylpyrazole and by the polyene citral. The toxicity and relatively low potency at inhibiting the epidermal alcohol dehydrogenase isoenzyme curtailed the use of 4-methylpyrazole in vivo. However, citral significantly inhibited retinoic acid formation from retinol in the epidermis in vivo. The ability to inhibit the oxidation of retinol to retinoic acid in mouse epidermis provides a potential method to resolve the roles of retinol and retinoic acid in epithelial function.
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Balasuriya, Nileeka, McShane McKenna, Xuguang Liu, Shawn Li, and Patrick O’Donoghue. "Phosphorylation-Dependent Inhibition of Akt1." Genes 9, no. 9 (September 7, 2018): 450. http://dx.doi.org/10.3390/genes9090450.
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Protein kinase B (Akt1) is a proto-oncogene that is overactive in most cancers. Akt1 activation requires phosphorylation at Thr308; phosphorylation at Ser473 further enhances catalytic activity. Akt1 activity is also regulated via interactions between the kinase domain and the N-terminal auto-inhibitory pleckstrin homology (PH) domain. As it was previously difficult to produce Akt1 in site-specific phosphorylated forms, the contribution of each activating phosphorylation site to auto-inhibition was unknown. Using a combination of genetic code expansion and in vivo enzymatic phosphorylation, we produced Akt1 variants containing programmed phosphorylation to probe the interplay between Akt1 phosphorylation status and the auto-inhibitory function of the PH domain. Deletion of the PH domain increased the enzyme activity for all three phosphorylated Akt1 variants. For the doubly phosphorylated enzyme, deletion of the PH domain relieved auto-inhibition by 295-fold. We next found that phosphorylation at Ser473 provided resistance to chemical inhibition by Akti-1/2 inhibitor VIII. The Akti-1/2 inhibitor was most effective against pAkt1T308 and showed four-fold decreased potency with Akt1 variants phosphorylated at Ser473. The data highlight the need to design more potent Akt1 inhibitors that are effective against the doubly phosphorylated and most pathogenic form of Akt1.
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Prinsloo, Denise, Sandra van Dyk, Anél Petzer, and Jacobus P. Petzer. "Monoamine Oxidase Inhibition by Kavalactones from Kava (Piper Methysticum)." Planta Medica 85, no. 14/15 (September 20, 2019): 1136–42. http://dx.doi.org/10.1055/a-1008-9491.
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AbstractMonoamine oxidases (MAOs) are key metabolic enzymes for neurotransmitter and dietary amines and are targets for the treatment of neuropsychiatric and neurodegenerative disorders. This study examined the MAO inhibition potential of kavain and other kavalactones from the roots of kava (Piper methysticum), a plant that has been used for its anxiolytic properties. (±)-Kavain was found to be a good potency in vitro inhibitor of human MAO-B with an IC50 of 5.34 µM. (±)-Kavain is a weaker MAO-A inhibitor with an IC50 of 19.0 µM. Under the same experimental conditions, the reference MAO inhibitor, curcumin, displays IC50 values of 5.01 µM and 2.55 µM for the inhibition of MAO-A and MAO-B, respectively. It was further established that (±)-kavain interacts reversibly and competitively with MAO-A and MAO-B with enzyme-inhibitor dissociation constants (Ki) of 7.72 and 5.10 µM, respectively. Curcumin in turn, displays a Ki value of 3.08 µM for the inhibition of MAO-A. Based on these findings, other kavalactones (dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin) were also evaluated as MAO inhibitors in this study. Yangonin proved to be the most potent MAO inhibitor with IC50 values of 1.29 and 0.085 µM for MAO-A and MAO-B, respectively. It may be concluded that some of the central effects (e.g., anxiolytic) of kava may be mediated by MAO inhibition.
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Mostafa, Amany S., Waleed A. Bayoumi, Mohamed El-Mesery, and Abdelaziz Elgaml. "Molecular Design and Synthesis of New 3,4-Dihydropyrimidin-2(1H)-Ones as Potential Anticancer Agents with VEGFR-2 Inhibiting Activity." Anti-Cancer Agents in Medicinal Chemistry 19, no. 3 (June 25, 2019): 310–22. http://dx.doi.org/10.2174/1871520618666180717125906.
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Background: Two series of 3,4-dihydropyrimidin-2(1H)-one derivatives were designed based on the main structural features characterizing reported anticancer compounds with potent VEGFR-2 inhibiting activity. Methods: All the target compounds were synthesized and investigated for their in vitro anticancer activity using MTT assay and NCI protocol. The most active compounds were further investigated for the VEGFR-2 inhibiting activity using enzyme inhibition assay. Results: Of these derivatives, compound 8b possessed significant activity against Caco-2 (IC50 of 24.9 µM) and MCF7 (IC50 of 29.4 µM), compound 10 showed excellent potency against HCT-116 (IC50 of 32.6 µM), HEPG2 (IC50 of 16.4 µM) and MCF7 (IC50 of 32.8 µM), while compound 11b exhibited moderate anticancer activity towards MCF7 (IC50 of 41.7µM). Both 8b and 10 exhibited good potency regarding the inhibition of vascular endothelial growth factor receptor 2 (VEGFR-2), with an IC50 of 14.00 and 21.62 nM, respectively. Conclusion: The activity was rationalized based on molecular docking study that supported their VEGFR-2 inhibitory activity; as indicated by their favorable binding with the active site.
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Galardy, R. E., and Z. P. Kortylewicz. "Inhibitors of angiotensin-converting enzyme containing a tetrahedral arsenic atom." Biochemical Journal 226, no. 2 (March 1, 1985): 447–54. http://dx.doi.org/10.1042/bj2260447.
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A series of tetrahedral oxo acids of Group VA and VIA elements and of silicon and boron were examined as inhibitors of angiotensin-converting enzyme. Arsenate is a competitive inhibitor with a Ki of 27 +/- 1 mM, at least 10-fold more potent than phosphate. Dimethylarsinate is a competitive inhibitor with a Ki of 70 +/- 9 mM, 2-fold more potent than dimethylphosphinate. Oxo acids of boron, silicon, antimony, sulphur and selenium are not inhibitors. On the basis of these results and the strong inhibition of this zinc metallopeptidase by substrate analogues containing a tetrahedral phosphorus atom, two substrate analogues containing a tetrahedral arsenic atom were prepared. 2-Arsonoacetyl-L-proline is a competitive inhibitor with a Ki of 18 +/- 7 mM, more than 2000-fold weaker than that of its phosphorus analogue 2-phosphonoacetyl-L-proline. 4-Arsono-2-benzylbutanoic acid is a mixed inhibitor with a Ki of 0.5 +/- 0.2 mM, indistinguishable in potency from its phosphorus analogue 2-benzyl-4-phosphonobutanoic acid.
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Güzel-Akdemir, Özlen, Simone Carradori, Rossella Grande, Kübra Demir-Yazıcı, Andrea Angeli, Claudiu T. Supuran, and Atilla Akdemir. "Development of Thiazolidinones as Fungal Carbonic Anhydrase Inhibitors." International Journal of Molecular Sciences 21, no. 8 (April 22, 2020): 2960. http://dx.doi.org/10.3390/ijms21082960.
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In our efforts to find new and selective thiazolidinone-based anti-Candida agents, we synthesized and tested 26 thiazolidinones against several Candida spp. and Gram-positive and Gram-negative bacteria. The compounds showed selective antifungal activity with potency similar to fluconazole and clotrimazole, while lacking strong antibacterial activity. Molecular docking and molecular dynamics studies were performed on Candida CYP51a1 and carbonic anhydrase (CA) enzymes to further suggest putative targets that could mediate the antifungal effects of these compounds. Finally, the compounds were tested in enzyme inhibition assays to assess their putative mechanism of action and showed promising KI values in the 0.1–10 µM range against the Candida glabrata β-CA enzyme CgNce103.
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OWENS, Raymond J., Cath CATTERALL, Dawn BATTY, John JAPPY, Annette RUSSELL, Bryan SMITH, Jimi O'CONNELL, and Martin J. PERRY. "Human phosphodiesterase 4A: characterization of full-length and truncated enzymes expressed in COS cells." Biochemical Journal 326, no. 1 (August 15, 1997): 53–60. http://dx.doi.org/10.1042/bj3260053.
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The type 4 phosphodiesterase (PDE) family comprises four enzymes (4A, 4B, 4C and 4D) that are characterized by their specificity for cAMP and selective inhibition by the antidepressant drug rolipram {4-[3-(cyclopentoxyl)-4-methoxyphenyl]2-pyrrolidone}. In common with other PDEs, they consist of a central conserved domain associated with catalytic activity in addition to two N-terminal upstream conserved regions (UCR1 and UCR2) that are unique to the type 4 enzymes. We have isolated a 2 kb cDNA encoding a full-length type 4A PDE {HS PDE4A4B [Bolger, Michaeli, Martins, St.John, Steiner, Rodgers, Riggs, Wigler and Ferguson (1993) Mol. Cell Biol. 13, 6558–6571]} from a human frontal cortex cDNA library. Northern blot analysis showed that the major PDE4A mRNA of 4.5 kb was widely distributed in different human tissues. The recombinant PDE4A expressed in COS cells had a molecular mass of approx. 117 kDa as revealed by SDS/PAGE/Western blotting with a PDE4A-specific antibody and was specific for cAMP with a Km of 4.8 μM. The enzyme activity was potently inhibited by R-rolipram (IC50 204 nM) and showed a 2.7-fold stereoselectivity over the S enantiomer. Analysis of the kinetics of inhibition indicated that R-rolipram did not behave as a simple competitive inhibitor. Dixon replots suggested that there was more than one mode of interaction consistent with the detection in the enzyme of a high-affinity binding site for R-rolipram with a Kd of 2.3 nM. Truncation of the PDE4A enzyme by deletion mutagenesis showed that neither of the UCRs was required for catalytic activity and identified an approx. 71 kDa core enzyme with a Km for cAMP of 3.3 μM. In contrast with the full-length PDE4A, R-rolipram behaved as a simple competitive inhibitor of this form of the enzyme with decreased potency (IC50 1022 nM) and no stereoselectivity. In addition, no high-affinity rolipram-binding site was detected in the truncated enzyme, indicating that this interaction involves sequences upstream of the catalytic domain of the enzyme.
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Sivaraman, Bhuvaneswari, Vijaykumar Raji, Bala Aakash Velmurugan, and Ramalakshmi Natarajan. "Acetylcholinesterase Enzyme Inhibitor Molecules with Therapeutic Potential for Alzheimer's Disease." CNS & Neurological Disorders - Drug Targets 21, no. 5 (June 2022): 427–49. http://dx.doi.org/10.2174/1871527320666210928160159.
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: Acetylcholinesterase (AchE), hydrolase enzyme, regulates the hydrolysis of acetylcholine neurotransmitter in the neurons. AchE is found majorly in the central nervous system at the site of cholinergic neurotransmission. It is involved in the pathophysiology of Alzheimer’s diseasecausing dementia, cognitive impairment, behavioral and psychological symptoms. Recent findings involved the inhibition of AchE that could aid in the treatment of Alzheimer's. Many drugs of different classes are being analyzed in the clinical trials and examined for their potency. Drugs that are used in the treatment of Alzheimer’s disease are donepezil, galantamine, tacrine, rivastigmine showing major adverse effects. To overcome this, researchers work on novel drugs to elicit inhibition. This review comprises many hybrids and non-hybrid forms of heteroaromatic and nonheteroaromatic compounds that were designed and evaluated for AchE inhibition by Ellman’s method of assay. These novel compounds may assist future perspectives in the discovery of novel moieties against Alzheimer’s disease by the inhibition of AchE.
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Gholivand, Khodayar, Ahlam Madani Alizadehgan, Fresia Mojahed, Gholamreza Dehghan, Azadeh Mohammadirad, and Mohammad Abdollahi. "Some New Carbacylamidophosphates as Inhibitors of Acetylcholinesterase and Butyrylcholinesterase." Zeitschrift für Naturforschung C 63, no. 3-4 (April 1, 2008): 241–50. http://dx.doi.org/10.1515/znc-2008-3-414.
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The differences in the inhibition activity of organophosphorus agents are a manifestation of different molecular properties of the inhibitors involved in the interaction with the active site of enzyme. We were interested in comparing the inhibition potency of four known synthesized carbacylamidophosphates with the general formula RC(O)NHP(O)Cl2, constituting organophosphorus compounds, where R = CCl3 (1), CHCl2 (2), CH2Cl (3) and CF3 (4), and four new ones with the general formula RC(O)NHP(O)(R′)2, where R′ = morpholine and R = CCl3 (5), CHCl2 (6), CH2Cl (7), CF3 (8), on AChE and BuChE activities. In addition, in vitro activities of all eight compounds on BuChE were determined. Besides, in vivo inhibition potency of compounds 2 and 6, which had the highest inhibition potency among the tested compounds, was studied. The data demonstrated that compound 2 from the compound series 1 to 4 and compound 6 from the compound series 5 to 8 are the most sensitive as AChE and BuChE inhibitors, respectively. Comparing the IC50 values of these compounds, it was clear that the inhibition potency of these compounds for AChE are 2- to 100-fold greater than for BuChE inhibition. Comparison of the kinetics (IC50, Ki, kp, KA and KD) of AChE and BuChE inactivation by these compounds resulted in no significant difference for the measured variables except for compounds 2 and 6, which appeared to be more sensitive to AChE and BuChE by significantly higher kp and Ki values and a lower IC50 value in comparison with the other compounds. The LD50 value of compounds 2 and 6, after oral administration, and the changes of erythrocyte AChE and plasma BuChE activities in albino mice were studied. The in vivo experiments, similar to the in vitro results, showed that compound 2 is a stronger AChE and BuChE inhibitor than the other synthesized carbacylamidophosphates. Furthermore, in this study, the importance of electropositivity of the phosphorus atom, steric hindrance and leaving group specificity were reinforced as important determinants of inhibition activity
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Green, Louis S., James M. Bullard, Wendy Ribble, Frank Dean, David F. Ayers, Urs A. Ochsner, Nebojsa Janjic, and Thale C. Jarvis. "Inhibition of Methionyl-tRNA Synthetase by REP8839 and Effects of Resistance Mutations on Enzyme Activity." Antimicrobial Agents and Chemotherapy 53, no. 1 (November 17, 2008): 86–94. http://dx.doi.org/10.1128/aac.00275-08.
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ABSTRACT REP8839 is a selective inhibitor of methionyl-tRNA synthetase (MetRS) with antibacterial activity against a variety of gram-positive organisms. We determined REP8839 potency against Staphylococcus aureus MetRS and assessed its selectivity for bacterial versus human orthologs of MetRS. The inhibition constant (Ki ) of REP8839 was 10 pM for Staphylococcus aureus MetRS. Inhibition of MetRS by REP8839 was competitive with methionine and uncompetitive with ATP. Thus, high physiological ATP levels would actually facilitate optimal binding of the inhibitor. While many gram-positive bacteria, such as Staphylococcus aureus, express exclusively the MetRS1 subtype, many gram-negative bacteria express an alternative homolog called MetRS2. Some gram-positive bacteria, such as Streptococcus pneumoniae and Bacillus anthracis, express both MetRS1 and MetRS2. MetRS2 orthologs were considerably less susceptible to REP8839 inhibition. REP8839 inhibition of human mitochondrial MetRS was 1,000-fold weaker than inhibition of Staphylococcus aureus MetRS; inhibition of human cytoplasmic MetRS was not detectable, corresponding to >1,000,000-fold selectivity for the bacterial target relative to its cytoplasmic counterpart. Mutations in MetRS that confer reduced susceptibility to REP8839 were examined. The mutant MetRS enzymes generally exhibited substantially impaired catalytic activity, particularly in aminoacylation turnover rates. REP8839 Ki values ranged from 4- to 190,000-fold higher for the mutant enzymes than for wild-type MetRS. These observations provide a potential mechanistic explanation for the reduced growth fitness observed with MetRS mutant strains relative to that with wild-type Staphylococcus aureus.
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Goedken, Eric R., Andrew I. Gagnon, Gary T. Overmeyer, Junjian Liu, Richard A. Petrillo, Andrew F. Burchat, and Medha J. Tomlinson. "HTRF-Based Assay for Microsomal Prostaglandin E2 Synthase-1 Activity." Journal of Biomolecular Screening 13, no. 7 (July 1, 2008): 619–25. http://dx.doi.org/10.1177/1087057108321145.
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Microsomal prostaglandin E2 synthase-1 (mPGES-1) catalyzes the formation of prostaglandin E2 (PGE2) from the endoperoxide prostaglandin H 2 (PGH2). Expression of this enzyme is induced during the inflammatory response, and mouse knockout experiments suggest it may be an attractive target for antiarthritic therapies. Assaying the activity of this enzyme in vitro is challenging because of the unstable nature of the PGH 2 substrate. Here, the authors present an mPGES-1 activity assay suitable for characterization of enzyme preparations and for determining the potency of inhibitor compounds. This plate-based competition assay uses homogenous time-resolved fluorescence to measure PGE2 produced by the enzyme. The assay is insensitive to DMSO concentration up to 10% and does not require extensive washes after the initial enzyme reaction is concluded, making it a simple and convenient way to assess mPGES-1 inhibition. ( Journal of Biomolecular Screening 2008:619-625)
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Klabe, Ronald M., Lee T. Bacheler, Paul J. Ala, Susan Erickson-Viitanen, and James L. Meek. "Resistance to HIV Protease Inhibitors: A Comparison of Enzyme Inhibition and Antiviral Potency." Biochemistry 37, no. 24 (June 1998): 8735–42. http://dx.doi.org/10.1021/bi972555l.
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Lamba, Doriano, and Alessandro Pesaresi. "Kinetic Modeling of Time-Dependent Enzyme Inhibition by Pre-Steady-State Analysis of Progress Curves: The Case Study of the Anti-Alzheimer’s Drug Galantamine." International Journal of Molecular Sciences 23, no. 9 (May 3, 2022): 5072. http://dx.doi.org/10.3390/ijms23095072.
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The Michaelis–Menten model of enzyme kinetic assumes the free ligand approximation, the steady-state approximation and the rapid equilibrium approximation. Analytical methods to model slow-binding inhibitors by the analysis of initial velocities have been developed but, due to their inherent complexity, they are seldom employed. In order to circumvent the complications that arise from the violation of the rapid equilibrium assumption, inhibition is commonly evaluated by pre-incubating the enzyme and the inhibitors so that, even for slow inhibitors, the binding equilibrium is established before the reaction is started. Here, we show that for long drug-target residence time inhibitors, the conventional analysis of initial velocities by the linear regression of double-reciprocal plots fails to provide a correct description of the inhibition mechanism. As a case study, the inhibition of acetylcholinesterase by galantamine, a drug approved for the symptomatic treatment of Alzheimer’s disease, is reported. For over 50 years, analysis based on the conventional steady-state model has overlooked the time-dependent nature of galantamine inhibition, leading to an erroneous assessment of the drug potency and, hence, to discrepancies between biochemical data and the pharmacological evidence. Re-examination of acetylcholinesterase inhibition by pre-steady state analysis of the reaction progress curves showed that the potency of galantamine has indeed been underestimated by a factor of ~100.
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Huppatz, John L., and John E. Casida. "Acetohydroxyacid Synthase Inhibitors: N-Phthalyl-ʟ-valine Anilide and Related Compounds." Zeitschrift für Naturforschung C 40, no. 9-10 (August 1, 1985): 652–56. http://dx.doi.org/10.1515/znc-1985-9-1010.
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Abstract The potency of ʟ-valine as an inhibitor of Zea mays acetohydroxyacid synthase (AHAS) is increased more than 80110-fold on conversion to its N-phthalyl anilide derivative which is active at 2 µᴍ. The ᴅ-valine, α-aminobutyric acid, isoleucine and phenylalanine analogs are 11- to 43-fold less potent, and similar N-phthalyl anilide derivatives of other branched-chain amino acids are essentially inactive. Full potency is retained on replacing the phthalimide moiety of the valine anilide with cyclohexane-1,2-dicarboximide or 1-cyclohexene-1.2-dicarboximide groups and partial activity with 4-cyclohexene-1,2-dicarboximide and methyl- or dimethylmaleimide groups. Inhibition of the enzyme and of root growth by the valine derivatives may result from binding at or near the site involved in feedback control of AHAS by ʟ-valine.
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Shen, L. L., and D. T. W. Chu. "Type II DNA Topoisomerases as Antibacterial Targets." Current Pharmaceutical Design 2, no. 2 (April 1996): 195–208. http://dx.doi.org/10.2174/1381612802666220921174531.
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DNA topoisomerases are a class of ubiquitous enzymes that maintain the topological structures of DNA in both prokaryotic and eukaryotic organisms. The enzymes catalyze DNA topoisomerization reactions through a sequential DNA breaking passing-resealing process, and are the targets of many important therapeutic agents for the treatment of cancer and bacterial infectious diseases. Quinolone antibacterial agents are known to target specifically to DNA gyrase, a bacterial type II DNA topoisomerase. The drugs have rapid bactericidal action that is believed to derive from their dual actions to inhibit the catalytic activity of the essential enzyme and, more importantly, to form a stable enzyme-DNA cleavable complex at a position ahead of the replication forks leading to a quick arrest of DNA replication, irreversible DNA damage and thus cell death. These inhibitors are small in size and simple in structure, but are extremely potent with the antibacterial potency reaching to a few nanograms per milliliter range. The high potency and specificity of these inhibitors is believed to be achieved by its unique capability to bind cooperatively to a partially denatured DNA pocket created by the target enzyme during the strand breaking passing steps of the catalysis. The inhibition model emphasizes the importance of the binding pocket conformation in determining the binding specificity and potency. This 'conformation-fitting model ' explains most structure-activity relationships of quinolones as well as observations in quinolone-resistance patterns. Recent publications imply that the target of quinolones may also be the bacterial topoisomerase IV, which is another essential type II enzyme discovered recently in E. coli and shown to be necessary for DNA segregation at the final stage of cell division. These two enzymes share high degree of sequence homology as well as quinolone sensitivity in vitro and in vivo. Results of genetic analysis of resistant mutants further support the notion that topoisomerase IV may be a primary target of quinolone action in Staphylococcus aureus.
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Nga, Bui T. T., Yuki Takeshita, Misa Yamamoto, and Yoshimi Yamamoto. "Studies of Inhibitory Mechanisms of Propeptide-Like Cysteine Protease Inhibitors." Enzyme Research 2014 (June 19, 2014): 1–10. http://dx.doi.org/10.1155/2014/848937.
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Mouse cytotoxic T-lymphocyte antigen-2α (CTLA-2α), Drosophila CTLA-2-like protein (crammer), and Bombyx cysteine protease inhibitor (BCPI) belong to a novel family of cysteine protease inhibitors (I29). Their inhibitory mechanisms were studied comparatively. CTLA-2α contains a cysteine residue (C75), which is essential for its inhibitory potency. The CTLA-2α monomer was converted to a disulfide-bonded dimer in vitro and in vivo. The dimer was fully inhibitory, but the monomer, which possessed a free thiol residue, was not. A disulfide-bonded CTLA-2α/cathepsin L complex was isolated, and a cathepsin L subunit with a molecular weight of 24,000 was identified as the interactive enzyme protein. Crammer also contains a cysteine residue (C72). Both dimeric and monomeric forms of crammer were inhibitory. A crammer mutant with Cys72 to alanine (C72A) was fully inhibitory, while the replacement of Gly73 with alanine (G73A) caused a significant loss in inhibitory potency, which suggests a different inhibition mechanism from CTLA-2α. BCPI does not contain cysteine residue. C-terminal region (L77-R80) of BCPI was essential for its inhibitory potency. CTLA-2α was inhibitory in the acidic pH condition but stabilized cathepsin L under neutral pH conditions. The different inhibition mechanisms and functional considerations of these inhibitors are discussed.
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Rodríguez Núñez, Yeray A., Margarita Gutíerrez, Jans Alzate-Morales, Francisco Adasme-Carreño, Fausto M. Güiza, Cristian C. Bernal, and Arnold R. Romero Bohórquez. "Tetrahydroquinoline-Isoxazole/Isoxazoline Hybrid Compounds as Potential Cholinesterases Inhibitors: Synthesis, Enzyme Inhibition Assays, and Molecular Modeling Studies." International Journal of Molecular Sciences 21, no. 1 (December 18, 2019): 5. http://dx.doi.org/10.3390/ijms21010005.
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A series of 44 hybrid compounds that included in their structure tetrahydroquinoline (THQ) and isoxazole/isoxazoline moieties were synthesized through the 1,3-dipolar cycloaddition reaction (1,3-DC) from the corresponding N-allyl/propargyl THQs, previously obtained via cationic Povarov reaction. In vitro cholinergic enzymes inhibition potential of all compounds was tested. Enzyme inhibition assays showed that some hybrids exhibited significant potency to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Especially, the hybrid compound 5n presented the more effective inhibition against AChE (4.24 µM) with an acceptable selectivity index versus BChE (SI: 5.19), while compound 6aa exhibited the greatest inhibition activity on BChE (3.97 µM) and a significant selectivity index against AChE (SI: 0.04). Kinetic studies were carried out for compounds with greater inhibitory activity of cholinesterases. Structure–activity relationships of the molecular hybrids were analyzed, through computational models using a molecular cross-docking algorithm and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) binding free energy approach, which indicated a good correlation between the experimental inhibition values and the predicted free binding energy.
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Malunga, Lovemore Nkhata, Marta Izydorczyk, and Trust Beta. "Antiglycemic Effect of Water Extractable Arabinoxylan from Wheat Aleurone and Bran." Journal of Nutrition and Metabolism 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/5784759.
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The studies on the effects of arabinoxylan (AX) polysaccharides on postprandial glucose response have resulted in contrasting results owing to the diversity in AX structures. Four water extractable AX (WEAX) extracts obtained from wheat aleurone and bran were used to investigate (a) the effect of AX on activities ofα-amylase andα-glucosidase, (b) influence of AX chemical composition on their inhibition potency, and (c) kinetics of enzyme inhibition.α-Amylase activity was not significantly affected by the presence WEAX fractions regardless of type or concentration. WEAX inhibitedα-glucosidase activity only when maltose was used as a substrate but not sucrose. The IC50 values of WEAX (4.88±0.3–10.14±0.5 mg/mL) were highly correlated to ferulic acid content (R=-0.89), arabinose to xylose ratio (R=-0.67), and relative proportions of xylose being unsubstituted (R=0.69), disubstituted (R=-0.63), and monosubstituted (R=-0.76). The Lineweaver–Burk plot suggested an uncompetitive enzyme inhibition mode. Thus, our results suggest that antiglycemic properties of WEAX may be derived from direct inhibition ofα-glucosidase activity.
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Matsuda, Y., S. Nakanishi, K. Nagasawa, K. Iwahashi, and H. Kase. "The effect of K-252a, a potent microbial inhibitor of protein kinase, on activated cyclic nucleotide phosphodiesterase." Biochemical Journal 256, no. 1 (November 15, 1988): 75–80. http://dx.doi.org/10.1042/bj2560075.
Full textAbstract:
K-252a, an indole carbazol compound of microbial origin, inhibited activation of bovine brain phosphodiesterase induced by calmodulin (CaM), sodium oleate, or limited proteolysis with almost equal potency. Kinetic analysis revealed that the CaM-activated phosphodiesterase (CaM-PDE) was competitively inhibited by K-252a with respect to CaM. On the other hand, inhibition of the trypsin-activated phosphodiesterase was competitive with respect to cyclic AMP. Addition of a lower amount of phosphatidylserine or sodium oleate to the reaction medium was efficacious in attenuating the inhibition of the CaM-PDE by W-7, compound 48/80, or calmidazolium but, in contrast, had no effect on the inhibition by K-252a. Furthermore, CaM-independent systems such as [3H]nitrendipine receptor binding or Na+ + K+-ATPase were influenced less by K-252a compared with W-7, compound 48/80 and calmidazolium. In conclusion, K-252a is an inhibitor of CaM-dependent cyclic nucleotide phosphodiesterase and it appears that it inhibits the enzyme not only via CaM antagonism but possibly also by interfering with the enzyme.
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Kalalinia, Fatemeh, Mohammad Jouya, Alireza K. Komachali, Seyed M. Aboutourabzadeh, Gholamreza Karimi, Javad Behravan, Khalil Abnous, Leila Etemad, Hossein Kamali, and Farzin Hadizadeh. "Design, Synthesis, and Biological Evaluation of New Azole Derivatives as Potent Aromatase Inhibitors with Potential Effects against Breast Cancer." Anti-Cancer Agents in Medicinal Chemistry 18, no. 7 (November 30, 2018): 1016–24. http://dx.doi.org/10.2174/1871520618666180116105858.
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Purpose: Some aromatase inhibitors are FDA-approved agents as first-line therapy in the treatment of endocrine-responsive breast cancer. In this study, we aimed to develop new azole derivatives with higher specificity and potency. Methods: New aromatase inhibitors were designed by Molecular Operating Environment (MOE) software and synthesized in a one-step SN2 reaction. These compounds were characterized by melting point, 1H- and 13CNMR, elemental analysis and mass spectra. The in vitro and in vivo aromatase inhibition of these compounds was evaluated using the Estrone ELISA assay, and by measuring the inhibition of androstenedione-induced uterine hypertrophy. The selectivity of aromatase inhibition was investigated by the inhibition of ACTH stimulation on the plasma concentrations of aldosterone and cortisol. Results: Docking simulations showed that four new azole derivatives could efficiently interact with enzyme active sites. The in vitro aromatase-inhibition assay showed that the compounds 1,3,5-tris(imidazol-1- ylmethyl)benzene (3b) and 1,3-Bis(imidazole-1- ylmethyl) benzene (3d) effectively inhibited aromatase, with IC50 values of 0.2 nM and 6.8 nM, respectively; these values were similar to known aromatase inhibitor letrozole (IC50 0.3 nM). The in vivo aromatase-inhibitory potency of compound 3b was similar to letrozole, although compound 3b acted more selectively. Conclusion: This report introduced a new compound that can be considered as a new lead for further investigation to explore more-potent and more-selective aromatase inhibitors.
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de Jonge, Boudewijn L. M., Grant K. Walkup, Sushmita D. Lahiri, Hoan Huynh, Georg Neckermann, Luke Utley, Tory J. Nash, et al. "Discovery of Inhibitors of 4′-Phosphopantetheine Adenylyltransferase (PPAT) To Validate PPAT as a Target for Antibacterial Therapy." Antimicrobial Agents and Chemotherapy 57, no. 12 (September 16, 2013): 6005–15. http://dx.doi.org/10.1128/aac.01661-13.
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ABSTRACTInhibitors of 4′-phosphopantetheine adenylyltransferase (PPAT) were identified through high-throughput screening of the AstraZeneca compound library. One series, cycloalkyl pyrimidines, showed inhibition of PPAT isozymes from several species, with the most potent inhibition of enzymes from Gram-positive species. Mode-of-inhibition studies withStreptococcus pneumoniaeandStaphylococcus aureusPPAT demonstrated representatives of this series to be reversible inhibitors competitive with phosphopantetheine and uncompetitive with ATP, binding to the enzyme-ATP complex. The potency of this series was optimized using structure-based design, and inhibition of cell growth of Gram-positive species was achieved. Mode-of-action studies, using generation of resistant mutants with targeted sequencing as well as constructs that overexpress PPAT, demonstrated that growth suppression was due to inhibition of PPAT. An effect on bacterial burden was demonstrated in mouse lung and thigh infection models, but further optimization of dosing requirements and compound properties is needed before these compounds can be considered for progress into clinical development. These studies validated PPAT as a novel target for antibacterial therapy.
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Hafifani, Witya, Indun D. Puspita, and Masagus M. P. Putra. "The effect of hydrolysis duration on the antibacterial activity of swamp eel head protein hydrolysate produced by papain against histamine-producing bacteria." E3S Web of Conferences 322 (2021): 04005. http://dx.doi.org/10.1051/e3sconf/202132204005.
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Swamp eel (Monopterus albus) processing produced byproducts such as heads that possess a high protein, carbohydrate, lipid, and energies content. Swamp eel heads were hydrolyzed (SEHPH) and tested for their antibacterial activity against histamine-producing bacteria (HPB) to explore the potency. The hydrolysis was conducted by a commercial papain enzyme PAYA (concentration 4%) with various hydrolysis times (0, 60, 120, and 180 minutes) at 60o C with pH 5. The results indicated that increasing hydrolysis time increased solubility and the degree of hydrolysis. The inhibitor concentration 50 test using microdilution of SEHPH inhibited 50% against three HPB named Citrobacter sp. (CK1), Klebsiella sp. (CK13), and Morganella morganii (TK7) at 20 mg/ml. The optimum antibacterial activity test by disk diffusion method was formed by each minute of hydrolysis with the best inhibition zone to Klebsiella sp. (CK13). The macrodillution method showed the highest inhibition was produced by 180 hydrolyses with 45% on CK1, 54% on CK13, and 48% on TK7. These results indicated that SEHPH has potency as an antibacterial agent to reduce histamine-producing bacteria.
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Rani, Nidhi, and Randhir Singh. "Molecular Modelling Studies of 1,4-Diaryl-2-Mercaptoimidazole Derivatives for Antimicrobial Potency." Current Computer-Aided Drug Design 15, no. 5 (September 23, 2019): 409–20. http://dx.doi.org/10.2174/1573409915666181219124956.
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Background: : Imidazoles are considered as potent antimicrobial agents. In view of this 2-mercaptoimidazoles were synthesized and evaluated for antimicrobial study. Methods:: Some new 2-mercaptoimidazoles 4a-r were synthesized using substituted aniline and substituted phenacyl bromides in the presence of anhydrous sodium carbonate or potassium carbonate and potassium thiocyanate under solvent-free conditions catalyzed by eco-friendly ptoluene sulfonic acid. Results: : The structure of compounds was evaluated on the basis of Infrared spectroscopy (IR), 1HNMR (proton nuclear magnetic resonance) and mass spectral studies. These novel compounds were screened for in-vitro antibacterial and antifungal potency against Staphyllococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Further, the study was rationalized by molecular modeling studies. All the compounds were subjected to molecular modeling studies for inhibition of enzyme 14α-demethylase. Conclusions:: The compounds were found to be effective in inhibiting the growth of pathogens. The in-silico results depicted that, all the synthesized compounds have minimum binding energy and good affinity towards the active site and thus can be considered as good inhibitors of 14α- demethylase enzyme.
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Giovanny, Lisa, Faliha Arinda Lestari, Nurul Marfira, Laksmi Ambarsari, and Siti Warnasih. "Potency of Ethanol Extracts Palm Seeds (Phoenix dactylifera L.) as Antidiabetic with Inhibition Kinetics Parameter." Current Biochemistry 6, no. 2 (February 3, 2020): 1–10. http://dx.doi.org/10.29244/cb.6.2.1.
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Dates seeds are one of the byproducts of the date palm juice industry which has the potential for further processing. Dates seeds contain active compounds that are known to have ability to inhibit αglucosidase. This study aims to measure the activity of 70% ethanol extract and the fraction of date palm seeds with a mechanism in inhibiting αglucosidase. The measurement of inhibitory activity was carried out by extracting date palm seeds using 70% water and ethanol. The extraction product is then fractionated with n-hexane, ethyl acetate, n-butanol, and water. Then the total phenolic and flavonoid calculations were calculated for each extract and fraction. Measurement of α-glucosidase inhibition activity was measured based on reaction of substrate to enzyme by the addition of inhibitors. The results showed that the ethanolextract had the highest total phenolic and flavonoid, which were 76.86 mg GAE / g and 21.19 mg QE / g, respectively. n-hexane fraction have the best inhibitory activity seen from the IC50 value, which is 12.69 mg/L. The kinetics of inhibition of 70% ethanol extract of date palm seeds are mixed inhibition.
Keywords: α-glucosidase, date seeds, flavonoids, kinetic inhibition, phenolics
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Humnabadkar, Vaishali, Prashanti Madhavapeddi, Halesha Basavarajappa, Md Gulebahar Sheikh, Rajendra Rane, Reetobrata Basu, Prateek Verma, Aishwarya Sundaram, Kakoli Mukherjee, and Sunita M. de Sousa. "Assays, Surrogates, and Alternative Technologies for a TB Lead Identification Program Targeting DNA Gyrase ATPase." Journal of Biomolecular Screening 20, no. 2 (October 9, 2014): 265–74. http://dx.doi.org/10.1177/1087057114554170.
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Mycobacterium tuberculosis (Mtb) DNA gyrase ATPase was the target of a tuberculosis drug discovery program. The low specific activity of the Mtb ATPase prompted the use of Mycobacterium smegmatis (Msm) enzyme as a surrogate for lead generation, since it had 20-fold higher activity. Addition of GyrA or DNA did not significantly increase the activity of the Msm GyrB ATPase, and an assay was developed using GyrB alone. Inhibition of the Msm ATPase correlated well with inhibition of Mtb DNA gyrase supercoiling across three chemical scaffolds, justifying its use. As the IC50 of compounds approached the enzyme concentration, surrogate assays were used to estimate potencies (e.g., the shift in thermal melt of Mtb GyrB, which correlated well with IC50s >10 nM). Analysis using the Morrison equation enabled determination of [Formula: see text]s in the sub-nanomolar range. Surface plasmon resonance was used to confirm these IC50s and measure the Kds of binding, but a fragment of Mtb GyrB had to be used. Across three scaffolds, the dissociation half life, t1/2, of the inhibitor-target complex was ≤8 min. This toolkit of assays was developed to track the potency of enzyme inhibition and guide the chemistry for progression of compounds in a lead identification program.
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FINNEY, Sarah, Lisa SEALE, Roy T. SAWYER, and Robert B. WALLIS. "Tridegin, a new peptidic inhibitor of factor XIIIa, from the blood-sucking leech Haementeria ghilianii." Biochemical Journal 324, no. 3 (June 15, 1997): 797–805. http://dx.doi.org/10.1042/bj3240797.
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1. Crude salivary gland extract of the giant Amazon leech, Haementeria ghilianii, contains an inhibitor of plasma factor XIIIa. 2. The inhibitory agent was purified to homogeneity by anion-exchange, cation-exchange, gel-filtration and reverse-phase chromatography to yield a single band on SDS/PAGE with an apparent molecular mass of 7.3 kDa. It has been named tridegin. 3. Micro-sequencing of proteolytic fragments showed tridegin to be a peptide of 66 amino acids. The sequence is unique with little similarity to other leech-derived proteins. 4. Inhibition of plasma factor XIIIa activity was confirmed by four independent methods: tridegin increased the solubility of fibrin clots in urea, inhibited ammonia produced from the incorporation of ethylamine into casein, inhibited the incorporation of 5′-(biotinamido)pentylamine into casein and prevented γ-dimer formation in clotting fibrinogen. 5. The IC50 of tridegin (approx. 9.2 nM) is very close to the concentration of factor XIIIa used in the assay and in fact depends on its concentration. This is the most potent inhibitor of factor XIIIa yet described. 6. Tridegin also inhibits platelet factor XIIIa (factor XIIIAa) with a similar potency to that of the plasma enzyme. 7. Tridegin also inhibits tissue transglutaminase but with lower potency and independently of the enzyme concentration. 8. Tridegin appears to be specific for transglutaminases, since it has no effect on the coagulation times of human plasma, on thrombin or factor Xa. Moreover it has no effect on other thiol-containing enzymes and has no ability to digest fibrinogen or cleave the isopeptide substrate, l-γ-glutamyl-4-nitroanilide.
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Asan, Tandiah, I. Nyoman Ehrich Lister, Edy Fachrial, Annisa Amalia, Wahyu Widowati, Buter Samin, and Liena Liena. "Potency of Black Soybean (Glycine max (L.) Merr) Extract and Daidzein as Antioxidant and Antihyaluronidase." Majalah Obat Tradisional 24, no. 1 (April 30, 2019): 52. http://dx.doi.org/10.22146/mot.43615.
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Black soybean (Glycine max (L.) Merr.) is a plant that is widely planted and consumed in Indonesia. In addition, black soybean has unique content of isoflavones, such as daidzein, which is one of the active compounds that have the effect of fighting free radicals and can inhibit the aging process. The purpose of this study is to analyze the antioxidant potency possessed by black soybean extract (BSE) and daidzeinin inhibiting aging of the skin. The method used is a colorimetric test. The type of antioxidant test used is H2O2 scavenging and inhibiting the activity of the hyaluronidase enzyme for antiaging. BSE has better effectiveness of H2O2 scavenging (IC50: 286.24±11.16 (µg/mL)) than daidzein compound (IC50: 366.16±2.54 (µg/mL)). In the inhibition of hyaluronidase enzyme, the daidzein has more effective activities (IC50: 95.80±3.98 (µg/mL)) compared to BSE (IC50: 152.56±13.98 (µg/mL)). The antioxidant and anti-aging activities possessed by BSE make it possible to be used as a cosmetic ingredient for skin aging therapy.
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Beattie, R. E., D. T. Elmore, C. H. Williams, and D. J. S. Guthrie. "The behaviour of leucine aminopeptidase towards thionopeptides." Biochemical Journal 245, no. 1 (July 1, 1987): 285–88. http://dx.doi.org/10.1042/bj2450285.
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Thionoleucine S-anilide (Leut-anilide), Leut-Gly-OEt and Leut-Phe-OMe were synthesized and shown to be competitive inhibitors of leucine aminopeptidase from pig kidney. The kinetics of inhibition were determined in the presence of leucine 4-methylcoumarin-7-amide as substrate. Although the compounds showed only moderate inhibitory potency, it was found that all were resistant to hydrolysis by the enzyme, in contrast with the reported behaviour of some thionopeptide analogues of substrates for other Zn2+-peptidases such as carboxypeptidase A and angiotensin-converting enzyme.
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Samira, Nia, Benarous Khedidja, Abdelalim Fatima Zahra, Chellali Khadidja Nour Elyakine, and Yousfi Mohamed. "In silico and in vitro Study of the Inhibitory Effect of Antiinflammatory Drug Betamethasone on Two Lipases." Anti-Inflammatory & Anti-Allergy Agents in Medicinal Chemistry 19, no. 4 (October 15, 2020): 387–92. http://dx.doi.org/10.2174/1871523018666190906165944.
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Background: For the first time, the anti-inflammatory drug betamethasone is investigated for its inhibitory activity against lipase. Objective: This work aims to demonstrate the in vitro and in silico inhibitory effect of the anti-inflammatory drug betamethasone on the enzymatic activity of two lipases. Methods: In vitro study using p-nitrophenyllaurate as lipase substrate is used to determine inhibition potency. Molecular Docking is performed using the Autodock Vina for drug molecule and two enzymes Candida rugosa lipase and human pancreatic lipase. Results: Betamethasone represents a moderate inhibition effect with a value of IC50 of 0.36±0.01 mg/ml. Molecular docking allowed us to understand inhibitory – enzyme interactions and to confirm in vitro obtained results. Conclusion: These experiments showed that betamethasone can be used in the treatment of diseases related to lipase activity.
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Hermanto, Sandra, Aldi Octavio, Azrifitria Azrifitria, and Susi Kusumaningrum. "The HMG-CoA Reductase Inhibitor Activities of Soy Protein Hydrolysates from Papain Hydrolysis." Molekul 16, no. 2 (July 20, 2021): 145. http://dx.doi.org/10.20884/1.jm.2021.16.2.724.
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The search for an HMG-CoA reductase inhibitor agent as a safe and inexpensive alternative treatment for hypercholesterolemia has been carried out using soy protein hydrolysates as one of the bioactive peptide sources. This study was conducted to explore the potency of soy protein hydrolysates as an anti hypercholesterolemia agent by an in vitro assay, through the inhibition capacity of the HMG-CoA (3-hydroxy-3-methyl glutaryl-coenzyme A) reductase enzyme as a key component of cholesterol biosynthesis. Sample preparation started with soy protein isolation through acid precipitation and separated by centrifugation. The samples were analyzed the proximate content and hydrolyzed by papain enzyme at concentration 0.2% (w/v), for 0-6 hours and at 37, 50, and 55 oC. The protein hydrolysates were subsequently evaluated for hydrolysis degree (% DH), hydrolysates profile with SDS-PAGE (Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis), and anti-cholesterol assay through HMG-CoA reductase inhibition tests. The sample with the highest inhibition activity was fractionated using gel filtration chromatography (Sephadex G-10) and the molecular weight of fractions was characterized by LCMS QTOF (Liquid Chromatography-Mass Spectrometry Quadrupole Time-of-Flight) for molecular weight determination. The results indicated the optimum hydrolysis conditions of soy protein isolates were obtained at 3 hours incubation, at 50 °C with DH 33.39% and the inhibition value was 95.65% (protein concentration 39.21 μg / mL). LCMS data showed the molecular weight of fractionated peptides were 1514 and 2029 Da. We assumed that both peptides have the same affinity as previous peptides in inhibiting HMG-CoA reductase.
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Baldwin, Jeffrey, Carolyn H. Michnoff, Nicholas A. Malmquist, John White, Michael G. Roth, Pradipsinh K. Rathod, and Margaret A. Phillips. "High-throughput Screening for Potent and Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase." Journal of Biological Chemistry 280, no. 23 (March 28, 2005): 21847–53. http://dx.doi.org/10.1074/jbc.m501100200.
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Plasmodium falciparum is the causative agent of the most serious and fatal malarial infections, and it has developed resistance to commonly employed chemotherapeutics. The de novo pyrimidine biosynthesis enzymes offer potential as targets for drug design, because, unlike the host, the parasite does not have pyrimidine salvage pathways. Dihydroorotate dehydrogenase (DHODH) is a flavin-dependent mitochondrial enzyme that catalyzes the fourth reaction in this essential pathway. Coenzyme Q (CoQ) is utilized as the oxidant. Potent and species-selective inhibitors of malarial DHODH were identified by high-throughput screening of a chemical library, which contained 220,000 drug-like molecules. These novel inhibitors represent a diverse range of chemical scaffolds, including a series of halogenated phenyl benzamide/naphthamides and urea-based compounds containing napthyl or quinolinyl substituents. Inhibitors in these classes with IC50 values below 600 nm were purified by high pressure liquid chromatography, characterized by mass spectroscopy, and subjected to kinetic analysis against the parasite and human enzymes. The most active compound is a competitive inhibitor of CoQ with an IC50 against malarial DHODH of 16 nm, and it is 12,500-fold less active against the human enzyme. Site-directed mutagenesis of residues in the CoQ-binding site significantly reduced inhibitor potency. The structural basis for the species selective enzyme inhibition is explained by the variable amino acid sequence in this binding site, making DHODH a particularly strong candidate for the development of new anti-malarial compounds.