Journal articles: 'Metal-Chelating Peptide'

1

Matsubara, Teruhiko, Yuko Hiura, and Katsuhiro Kawashiro. "Biocombinatorial Selection of Metal Ion-Chelating Peptides." International Journal of Modern Physics B 17, no. 08n09 (April 10, 2003): 1324–28. http://dx.doi.org/10.1142/s0217979203018946.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

A phage-displayed library selection was performed to obtain metal ion-chelating peptides. A dodecamer (12-mer) random peptide library was displayed on the surface of filamentous bacterial phage and subjected to an affinity selection. Four rounds of the selection gave fourteen Zn2+-positive phage clones. Enzyme-linked immunosorbent assay showed that the selected clones specifically bound to Zn2+ and Ni2+, but not to Cu2+ and Fe3+. Deduced amino acid sequences of the clones had histidine-rich consensus motifs. These chelating peptides should be applied to designing for metal ion-trapping biomaterials.

2

Kani, Hatice K., Ebru K. Kocazorbaz, and Figen Zihnioglu. "Investigation and isolation of peptide based antiglycating agents from various sources." Turkish Journal of Biochemistry 44, no. 5 (October 25, 2019): 699–705. http://dx.doi.org/10.1515/tjb-2018-0294.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Background In this work, peptide based antiglycation agents from various sources against the advanced glycation endproducts (AGE) formation was investigated. Materials and methods As a source of peptides with deglycating activity, Glycine max, Hordeum vulgare, Triticum aestivum, Avena sativa, Prunus dulcis ve Juglans regia were used. The metal chelating activity and antioxidant activity were determined by Cu(II) chelating activity and CUPRAC (Cupric Reducing Antioxidant Capacity) methods. Antidiabetic activity was evaluated through BSA-glucose model. Results Most of the extracts obtained have inhibitory activity against AGE formation. Among all plant peptide isolates soybean was found to be most efficient by means of antiglycating (IC50 1.33 μg/mL), antioxidant (28.2 ± 1.4 μmol AAE/mg) and metal chelation activity (55%). Conclusion As a result, this study can provide preliminary data to literature to support researches those focused on peptide based glycation inhibitors and discovery of potent AGE inhibitory peptides.

3

Chan, Pei-Teng, Patricia Matanjun, Cahyo Budiman, Rossita Shapawi, and Jau-Shya Lee. "Novel Peptide Sequences with ACE-Inhibitory and Antioxidant Activities Derived from the Heads and Bones of Hybrid Groupers (Epinephelus lanceolatus × Epinephelus fuscoguttatus)." Foods 11, no. 24 (December 9, 2022): 3991. http://dx.doi.org/10.3390/foods11243991.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

The heads and bones of hybrid groupers are potential precursors for angiotensin-converting enzyme (ACE)-inhibitory and antioxidant peptides. The aim of this study was to isolate the dual-action peptides from the Alcalase-treated head and bone hydrolysate of hybrid groupers followed by identification of the novel peptides. The stability of these peptides against stimulated in vitro gastrointestinal digestion (SGID) was also determined. Fraction HB-IV (less than 1 kDa) obtained from ultrafiltration showed the strongest ACE-inhibition ability (IC50: 0.28 mg/mL), which was comparable to the potency of the commercial supplement, PeptACE (IC50: 0.22 mg/mL). This fraction also demonstrated the highest hydroxyl radical scavenging and metal-chelating activities. However, further fractionation of HB-IV by a series of chromatography resulted in peptide fractions of reduced ACE-inhibitory and antioxidant activities. The hydroxyl radical scavenging and reduction potential of HB-IV were enhanced, whereas ACE-inhibitory and metal-chelating activities were reduced following SGID. A total of 145 peptide sequences were identified from HB-IV, of which 137 peptides were novel to the BIOPEP database. The results suggested that the bioactive peptides isolated from the heads and bones of hybrid groupers could be used as functional foods/ingredients with potential ACE-inhibitory and antioxidant effects.

4

Smith, M. C., T. C. Furman, J. A. Cook, T. Ingolia, and H. Hsiung. "Chelating peptide-immobilized metal ion affinity chromatography." Journal of Inorganic Biochemistry 36, no. 3-4 (August 1989): 277. http://dx.doi.org/10.1016/0162-0134(89)84385-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Daubit, Isabelle Marie, and Nils Metzler-Nolte. "On the interaction of N-heterocyclic carbene Ir+I complexes with His and Cys containing peptides." Dalton Transactions 48, no. 36 (2019): 13662–73. http://dx.doi.org/10.1039/c9dt01338e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

In the interaction of an [Ir(+i)(COD)(NHC)Cl] complex with model peptides a chelating motif with a particularly interesting bimetallic peptide-bridged Ir(+iii)–NHC motif was identified with loss of the COD and Cl ligands and oxidation of the metal.

6

Alies, Bruno, Jacob D. Wiener, and Katherine J. Franz. "A prochelator peptide designed to use heterometallic cooperativity to enhance metal ion affinity." Chemical Science 6, no. 6 (2015): 3606–10. http://dx.doi.org/10.1039/c5sc00602c.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Irankunda, Rachel, Jairo Andrés Camaño Echavarría, Cédric Paris, Loïc Stefan, Stéphane Desobry, Katalin Selmeczi, Laurence Muhr, and Laetitia Canabady-Rochelle. "Metal-Chelating Peptides Separation Using Immobilized Metal Ion Affinity Chromatography: Experimental Methodology and Simulation." Separations 9, no. 11 (November 14, 2022): 370. http://dx.doi.org/10.3390/separations9110370.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Metal-Chelating Peptides (MCPs), obtained from protein hydrolysates, present various applications in the field of nutrition, pharmacy, cosmetic etc. The separation of MCPs from hydrolysates mixture is challenging, yet, techniques based on peptide-metal ion interactions such as Immobilized Metal Ion Affinity Chromatography (IMAC) seem to be efficient. However, separation processes are time consuming and expensive, therefore separation prediction using chromatography modelling and simulation should be necessary. Meanwhile, the obtention of sorption isotherm for chromatography modelling is a crucial step. Thus, Surface Plasmon Resonance (SPR), a biosensor method efficient to screen MCPs in hydrolysates and with similarities to IMAC might be a good option to acquire sorption isotherm. This review highlights IMAC experimental methodology to separate MCPs and how, IMAC chromatography can be modelled using transport dispersive model and input data obtained from SPR for peptides separation simulation.

8

Luisi, Grazia, Azzurra Stefanucci, Gokhan Zengin, Marilisa Dimmito, and Adriano Mollica. "Anti-Oxidant and Tyrosinase Inhibitory In Vitro Activity of Amino Acids and Small Peptides: New Hints for the Multifaceted Treatment of Neurologic and Metabolic Disfunctions." Antioxidants 8, no. 1 (December 26, 2018): 7. http://dx.doi.org/10.3390/antiox8010007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Oxidative damage is among the factors associated with the onset of chronic pathologies, such as neurodegenerative and metabolic diseases. Several classes of anti-oxidant compounds have been suggested as having a protective role against cellular stressors, but, in this perspective, peptides’ world represents a poorly explored source. In the present study, the free radical scavenging properties, the metal ion reducing power, and the metal chelating activity of a series of sulfurated amino acids and tripeptides were determined in vitro through canonical assays (DPPH, ABTS, CUPRAC, FRAP, PM, and EECC) and estimated in comparison with the corresponding activities of synthetic peptide semicarbazones, incorporating the peculiar non-proteinogenic amino acid, tert-leucine (tLeu). The compounds exhibited remarkable anti-oxidant properties. As expected, sulfurated compounds 1–5 were found to be the most efficient radical scavengers and strongest reductants. Nevertheless, tLeu-containing peptides 7 and 8 disclosed notable metal reducing and chelating activities. These unprecedented results indicate that tLeu-featuring di- and tripeptide backbones, bearing the semicarbazone chelating moiety, are compatible with the emergence of an anti-oxidant potential. Additionally, when tested against a panel of enzymes usually targeted for therapeutic purposes in neurodegenerative and metabolic disorders, all samples were found to be good inhibitors of tyrosinase.

9

Lupaescu, Ancuta-Veronica, Ion Sandu, Brindusa Alina Petre, Laura Ion, Catalina-Ionica Ciobanu, and Gabi Drochioiu. "NAP Neuroprotective Peptide and its Analogs: Simultaneously Copper and Iron Binding and Reduction." Revista de Chimie 70, no. 5 (June 15, 2019): 1784–90. http://dx.doi.org/10.37358/rc.19.5.7215.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Neurodegenerative diseases, including Alzheimer disease, involve mechanisms such as protein aggregation, free radical generation and oxidative stress. Transition metals such as copper and iron were linked to neurodegenerative pathology. Their pathogenic role consists in generating different reactive oxygen species and damaging tissues or cells through the Fenton reaction. Abnormal metabolism of copper and iron can lead to several chronic pathogenesis. NAP is a small active fragment of activity-dependent neuroprotective protein essential for brain formation. NAP peptide showed neuroprotective proprieties against toxicity induced by the �-amyloid peptide, N-methyl-D-aspartate, electrical blockade, the envelope protein of the AIDS virus, dopamine, H2O2, and nutrient starvation in cell culture. Therefore, we investigated here the interaction of Cu2+ and Fe3+ ions with the NAP neuroprotective peptide and its analogs. With MALDI-ToF mass spectrometry, the formation of reduced metal-peptide complexes and the metal chelating properties of NAP-like neuroprotective peptides were highlighted.

10

Dayob, Kenana, Aygul Zengin, Ruslan Garifullin, Mustafa O. Guler, Timur I. Abdullin, Abdulla Yergeshov, Diana V. Salakhieva, Hong Hanh Cong, and Mohamed Zoughaib. "Metal-Chelating Self-Assembling Peptide Nanofiber Scaffolds for Modulation of Neuronal Cell Behavior." Micromachines 14, no. 4 (April 19, 2023): 883. http://dx.doi.org/10.3390/mi14040883.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Synthetic peptides are promising structural and functional components of bioactive and tissue-engineering scaffolds. Here, we demonstrate the design of self-assembling nanofiber scaffolds based on peptide amphiphile (PA) molecules containing multi-functional histidine residues with trace metal (TM) coordination ability. The self-assembly of PAs and characteristics of PA nanofiber scaffolds along with their interaction with Zn, Cu, and Mn essential microelements were studied. The effects of TM-activated PA scaffolds on mammalian cell behavior, reactive oxygen species (ROS), and glutathione levels were shown. The study reveals the ability of these scaffolds to modulate adhesion, proliferation, and morphological differentiation of neuronal PC-12 cells, suggesting a particular role of Mn(II) in cell-matrix interaction and neuritogenesis. The results provide a proof-of-concept for the development of histidine-functionalized peptide nanofiber scaffolds activated with ROS- and cell-modulating TMs to induce regenerative responses.

11

Krasae, K., W. Worawattanamateekul, and J. HInsui. "Effects of peptide fractions and amino acids on antioxidant properties of autolyzed tuna viscera protein hydrolysate." Food Research 7, no. 5 (October 5, 2023): 156–63. http://dx.doi.org/10.26656/fr.2017.7(5).270.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Tuna viscera as a common waste product from the tuna processing industry contributes to environmental pollution. The effects were determined of peptide fractions and amino acids on the antioxidant properties of protein hydrolysate from tuna viscera. We converted this waste into protein hydrolysate, a high added-value product, using autolysis. Tuna protein hydrolysate was fractionated by ultrafiltration into four fractions (>10 kDa, 5–10 kDa, 1–5 kDa and <1 kDa) and each was examined for its antioxidant properties (DPPH, ABTS, FRAP and metal chelating) and amino acids composition. The MW and amino acids of the tuna protein hydrolysate peptide fractions were not directly correlated with DPPH radical scavenging activity and metal chelating. The ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) of the 1–5 kDa fraction were higher than for the other fractions. The tuna protein hydrolysate peptide fractions contributed to antioxidant activity and should be used to their full advantage by the nutritional and food industries

12

Chen, Lei, Xuanri Shen, and Guanghua Xia. "Effect of Molecular Weight of Tilapia (Oreochromis Niloticus) Skin Collagen Peptide Fractions on Zinc-Chelating Capacity and Bioaccessibility of the Zinc-Peptide Fractions Complexes in Vitro Digestion." Applied Sciences 10, no. 6 (March 17, 2020): 2041. http://dx.doi.org/10.3390/app10062041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

To investigate the effect of the molecular weight of tilapia skin collagen peptide fractions on their zinc chelation capacity and the bioaccessibility of their zinc complexes, we evaluated the zinc-chelating ability of different molecular weight peptide, the solubility, and the stability of the complexes during simulated in vitro digestion. Low molecular weight peptide (P1) exhibited a higher zinc-chelating ability, which can be attributed to the variety of metal chelate amino acid residues. The highest solubility and the lowest release of zinc during peptic digestion for the P1-zinc complex and the zinc binding to P1 were retained at approximately 50% after peptic-pancreatic digestion. Fourier transform infrared spectroscopy indicated the primary involvement of the N-H group in all peptide-zinc complexes. This finding suggests that low molecular weight peptidefraction with strong zinc chelation ability can be used as delivery agents to improve zinc bioaccessibility.

13

Irankunda, Rachel, Jairo Andrés Camaño Echavarría, Cédric Paris, Katalin Selmeczi, Loïc Stefan, Sandrine Boschi-Muller, Laurence Muhr, and Laetitia Canabady-Rochelle. "Deciphering Interactions Involved in Immobilized Metal Ion Affinity Chromatography and Surface Plasmon Resonance for Validating the Analogy between Both Technologies." Inorganics 12, no. 1 (January 16, 2024): 31. http://dx.doi.org/10.3390/inorganics12010031.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Various peptides can be obtained through protein enzymatic hydrolysis. Immobilized metal ion affinity chromatography (IMAC) is one of the methods which can be used to separate metal chelating peptides (MCPs) in a hydrolysate mixture. In this context, this work aims to understand deeply the interactions in IMAC and surface plasmon resonance (SPR) in order to validate experimentally the analogy between both technologies and to be further able to perform IMAC modeling in the next work using peptide sorption isotherm parameters obtained from SPR. Indeed, chromatography modeling can be used to predict separation of MCPs in IMAC and the knowledge of peptide sorption isotherm obtained from SPR is a crucial step. For this purpose, 22 peptides were selected and investigated in IMAC using HisTrap X-Ni2+ and HiFliQ NTA-Ni2+ columns and were also studied in SPR as well. Results showed that peptides with histidine residues had good affinity to Ni2+, while the high positive charge of peptides was responsible of ionic interactions. Further, most of the peptides with good retention time in IMAC showed a good affinity in SPR as well, which validated experimentally the SPR-IMAC analogy.

14

Magrì, Antonio, Diego La Mendola, and Enrico Rizzarelli. "Nerve Growth Factor Peptides Bind Copper(II) with High Affinity: A Thermodynamic Approach to Unveil Overlooked Neurotrophin Roles." International Journal of Molecular Sciences 22, no. 10 (May 11, 2021): 5085. http://dx.doi.org/10.3390/ijms22105085.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Nerve growth factor (NGF) is a protein essential to neurons survival, which interacts with its receptor as a non-covalent dimer. Peptides belonging to NGF N-terminal domain are able to mimic the activity of the whole protein. Such activity is affected by the presence of copper ions. The metal is released in the synaptic cleft where proteins, not yet identified, may bind and transfer to human copper transporter 1 (hCtr1), for copper uptake in neurons. The measurements of the stability constants of copper complexes formed by amyloid beta and hCtr1 peptide fragments suggest that beta-amyloid (Aβ) can perform this task. In this work, the stability constant values of copper complex species formed with the dimeric form of N-terminal domain, sequence 1–15 of the protein, were determined by means of potentiometric measurements. At physiological pH, NGF peptides bind one equivalent of copper ion with higher affinity of Aβ and lower than hCtr1 peptide fragments. Therefore, in the synaptic cleft, NGF may act as a potential copper chelating molecule, ionophore or chaperone for hCtr1 for metal uptake. Copper dyshomeostasis and mild acidic environment may modify the balance between metal, NGF, and Aβ, with consequences on the metal cellular uptake and therefore be among causes of the Alzheimer’s disease onset.

15

Thompson, Channing C., and Rebecca Y. Lai. "Threonine Phosphorylation of an Electrochemical Peptide-Based Sensor to Achieve Improved Uranyl Ion Binding Affinity." Biosensors 12, no. 11 (November 2, 2022): 961. http://dx.doi.org/10.3390/bios12110961.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

We have successfully designed a uranyl ion (U(VI)-specific peptide and used it in the fabrication of an electrochemical sensor. The 12-amino acid peptide sequence, (n) DKDGDGYIpTAAE (c), originates from calmodulin, a Ca(II)-binding protein, and contains a phosphothreonine that enhances the sequence’s affinity for U(VI) over Ca(II). The sensing mechanism of this U(VI) sensor is similar to other electrochemical peptide-based sensors, which relies on the change in the flexibility of the peptide probe upon interacting with the target. The sensor was systematically characterized using alternating current voltammetry (ACV) and cyclic voltammetry. Its limit of detection was 50 nM, which is lower than the United States Environmental Protection Agency maximum contaminant level for uranium. The signal saturation time was ~40 min. In addition, it showed minimal cross-reactivity when tested against nine different metal ions, including Ca(II), Mg(II), Pb(II), Hg(II), Cu(II), Fe(II), Zn(II), Cd(II), and Cr(VI). Its reusability and ability to function in diluted aquifer and drinking water samples were further confirmed and validated. The response of the sensor fabricated with the same peptide sequence but with a nonphosphorylated threonine was also analyzed, substantiating the positive effects of threonine phosphorylation on U(VI) binding. This study places emphasis on strategic utilization of non-standard amino acids in the design of metal ion-chelating peptides, which will further diversify the types of peptide recognition elements available for metal ion sensing applications.

16

Meiss, Cade J., Paige J. Bothwell, and Michael I. Webb. "Ruthenium(II)–arene complexes with chelating quinoline ligands as anti-amyloid agents." Canadian Journal of Chemistry 100, no. 1 (January 2022): 18–24. http://dx.doi.org/10.1139/cjc-2021-0180.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Recent recognition of the soluble form of the amyloid-beta (Aβ) peptide as a neurotoxic agent in Alzheimer’s disease (AD) has spurred the development of agents to target this species. Because Aβ is known to chelate metal ions in solution, metal-based therapeutics are uniquely suited to exploit this affinity, where coordination to Aβ has been shown to impact the neurotoxicity of the peptide. Ruthenium(II)–arene complexes are unique candidates for evaluation, as one face of the molecule is blocked by the hydrophobic arene ring, while coordination to the Aβ peptide can occur on the other side of the molecule. We have prepared and evaluated two Ru(II)–arene complexes with chelating quinoline-based ligands, Ru1 and Ru2, for their respective anti-amyloid abilities. Although both complexes decreased the aggregation of soluble Aβ, Ru1 displayed promise in disrupting formed aggregates of the peptide. These findings represent an exciting new avenue for therapeutic development in AD, where both sides of the aggregation equilibrium are affected.

17

Smith, Michele C., Thomas C. Furman, and Charles Pidgeon. "Immobilized iminodiacetic acid metal peptide complexes. Identification of chelating peptide purification handles for recombinant proteins." Inorganic Chemistry 26, no. 12 (June 1987): 1965–69. http://dx.doi.org/10.1021/ic00259a030.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Iavorschi, Monica, Ancuța-Veronica Lupăescu, Laura Darie-Ion, Maria Indeykina, Gabriela Elena Hitruc, and Brîndușa Alina Petre. "Cu and Zn Interactions with Peptides Revealed by High-Resolution Mass Spectrometry." Pharmaceuticals 15, no. 9 (August 31, 2022): 1096. http://dx.doi.org/10.3390/ph15091096.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by abnormal extracellular amyloid-beta (Aβ) peptide depositions in the brain. Among amorphous aggregates, altered metal homeostasis is considered a common risk factor for neurodegeneration known to accelerate plaque formation. Recently, peptide-based drugs capable of inhibiting amyloid aggregation have achieved unprecedented scientific and pharmaceutical interest. In response to metal ions binding to Aβ peptide, metal chelation was also proposed as a therapy in AD. The present study analyzes the interactions formed between NAP octapeptide, derived from activity-dependent neuroprotective protein (ADNP), amyloid Aβ(9-16) fragment and divalent metal ions such as Cu and Zn. The binding affinity studies for Cu and Zn ions of synthetic NAP peptide and Aβ(9-16) fragment were investigated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ion trap mass spectrometry (ESI-MS) and atomic force microscopy (AFM). Both mass spectrometric methods confirmed the formation of metal–peptide complexes while the AFM technique provided morphological and topographic information regarding the influence of metal ions upon peptide crystallization. Our findings showed that due to a rich histidine center, the Aβ(9-16) fragment is capable of binding metal ions, thus becoming stiff and promoting aggregation of the entire amyloid peptide. Apart from this, the protective effect of the NAP peptide was found to rely on the ability of this octapeptide to generate both chelating properties with metals and interactions with Aβ peptide, thus stopping its folding process.

19

Irankunda, Rachel, Pauline Jambon, Alexandra Marc, Jairo Andrés Camaño Echavarría, Laurence Muhr, and Laetitia Canabady-Rochelle. "Simulation of Ni2+ Chelating Peptides Separation in IMAC: Prediction of Langmuir Isotherm Parameters from SPR Affinity Data." Processes 12, no. 3 (March 15, 2024): 592. http://dx.doi.org/10.3390/pr12030592.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Chromatography modeling for simulation is a tool that can help to predict the separation of molecules inside the column. Knowledge of sorption isotherms in chromatography modeling is a crucial step and methods such as frontal analysis or batch are used to obtain sorption isotherm parameters, but they require a significant quantity of samples. This study aims to predict Langmuir isotherm parameters from Surface Plasmon Resonance (SPR) affinity data (requiring less quantity of sample) to simulate metal chelating peptides (MCPs) separation in Immobilized Metal ion Affinity Chromatography (IMAC), thanks to the analogy between both techniques. The validity of simulation was evaluated by comparing the peptide’s simulated retention time with its experimental retention time obtained by IMAC. Results showed that the peptide affinity constant (KA) can be conserved between SPR and IMAC. However, the maximal capacity (qmax) must be adjusted by a correction factor to overcome the geometry differences between IMAC (spherical particles) and SPR (plane sensor ship). Therefore, three approaches were studied; the best one was to use qmax,IMAC imidazole determined experimentally while a correction factor was applied on qmax,SPR to obtain the qmax,IMAC of the peptide, thus minimizing the discrepancy between the experimental and simulated retention times of a peptide.

20

Chunkao, Siriporn, Wirote Youravong, Chutha T. Yupanqui, Adeola M. Alashi, and Rotimi E. Aluko. "Structure and Function of Mung Bean Protein-Derived Iron-Binding Antioxidant Peptides." Foods 9, no. 10 (October 3, 2020): 1406. http://dx.doi.org/10.3390/foods9101406.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

An iron-binding mung bean protein hydrolysate (MBPH) was prepared using a continuous enzymatic membrane reactor followed by peptide separation on anion-exchange (AEC) and reverse-phase HPLC (RP-HPLC) columns. Amino acid sequences of peptides present in the RP-HPLC fraction with the strongest iron-binding capacity were identified using mass spectrometry, and ten peptides of 5–8 amino acids synthesized for antioxidant characterization. Five fractions (AF1– AF5) with higher iron-binding capacity (88.86 ± 6.43 to 153.59 ± 2.18 mg/g peptide) when compared to the MBPH (36.81 ± 0.93 mg/g peptide) were obtained from AEC. PAIDL had the significantly (p < 0.05) highest iron-binding capacity, but LLLLG and LLGIL showed the strongest metal chelating activity. However, PAIDL (46.63%) and LLGIL (81.27%) had significantly (p < 0.05) better DPPH radical scavenging activity than the other peptides. PAIDL and LLGIL were also the most effective (p < 0.05) hydroxyl radical neutralizers with an effective concentration that scavenged 50% (EC50) values of 0.09 and 0.37 mM, respectively. PAIDL and AIVIL showed the lowest EC50 values of 0.07 mM each for superoxide radical scavenging activity. We conclude that short chain length in combination with leucine as the C-terminal amino acid residue contributed to the strong antioxidant properties of peptides in this study.

21

Sonklin, Chanikan, Natta Laohakunjit, and Orapin Kerdchoechuen. "Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates." PeerJ 6 (July 27, 2018): e5337. http://dx.doi.org/10.7717/peerj.5337.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Background Bioactive peptides can prevent damage associated with oxidative stress in humans when consumed regularly. Recently, peptides have attracted immense interest because of their beneficial functional properties, safety and little or no side effects when used at high concentration. Most antioxidant peptides are small in size, less than 1 kDa, and contains a high proportion of hydrophobic amino acid. Particularly, tyrosine, leucine, alanine, isoleucine, valine, lysine, phenyalanine, cysteine, methionine and histidine in peptide chain exhibited high antioxidant activity. Mungbean meal protein (MMP) is highly abundant in hydrophobic amino acids. It indicated that MMP might be a good source of antioxidants. Therefore, the objectives were to optimize the conditions used to generate mungbean meal protein hydrolysate (MMPH) with antioxidant activity from bromelain and to investigate the antioxidant activities of different molecular weight (MW) peptide fraction. Methods Response Surface Methodology (RSM) was used for screening of the optimal conditions to produce MMPH. After that MMPH was fractionated using ultrafiltration membranes with different MW distributions. Crude-MMPH and four fractions were investigated for five antioxidant activities: 2,2,1-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, ferric reducing antioxidant power (FRAP) and metal ion chelation activity. Results The optimal condition to produce the MMPH was 15% (w/w) of bromelain and hydrolysis time for 12 h which showed the greatest DPPH and ABTS radical scavenging activity. After mungbean protein from optimal condition was separated based on different molecular weight, the DPPH radical scavenging activity was the highest for the F4 (less than 1 kDa) peptide fraction. Metal ion chelating activity was generally weak, except for the F4 that had a value of 43.94% at a protein concentration of 5 mg/mL. The F4 also exhibited high hydroxyl and superoxide activities (54 and 65.1%), but moderate activity for ferric reducing antioxidant power (0.102 mmole Fe2+/g protein) compared to other peptide fractions and crude-MMPH. Molecular weight and amino acid were the main factors that determined the antioxidant activities of these peptide fractions. Results indicated that F4 had strong antioxidant potentials. Discussion The lowest MW fraction (less than 1 kDa) contributed to the highest DPPH, superoxide, hydroxyl and metal chelation activity because influence of low MW and high content of hydrophobic amino acid in peptide chain. Results from this study indicated that MMPH peptides donate protons to free radicals because they had significantly high DPPH value compared to superoxide, hydroxyl and FRAP, which reactions were electron donation. Moreover, MMPH peptides had the ability to inhibit transition metal ions because of highly abundant glutamic acid and aspartic acid in peptide chain.

22

Reutzel, Jan, Timm M. Diogo, and Armin Geyer. "Reversible Folding of a β-Hairpin Peptide by a Metal-Chelating Amino Acid." Chemistry - A European Journal 23, no. 35 (May 2, 2017): 8450–56. http://dx.doi.org/10.1002/chem.201700698.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Bellotti, Denise, Cinzia Tocchio, Remo Guerrini, Magdalena Rowińska-Żyrek, and Maurizio Remelli. "Thermodynamic and spectroscopic study of Cu(ii) and Zn(ii) complexes with the (148–156) peptide fragment of C4YJH2, a putative metal transporter of Candida albicans." Metallomics 11, no. 12 (2019): 1988–98. http://dx.doi.org/10.1039/c9mt00251k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

The linker sequence between the two main Cu(ii) and Zn(ii) coordination sites of C4YJH2, a putative metal transporter of Candida albicans, contributes in a non-negligible way to the protein chelating capability.

24

Bíró, Linda, András Ozsváth, Réka Kapitány, and Péter Buglyó. "Pd(II) Binding Strength of a Novel Ambidentate Dipeptide-Hydroxypyridinonate Ligand; A Solution Equilibrium Study." Molecules 27, no. 14 (July 21, 2022): 4667. http://dx.doi.org/10.3390/molecules27144667.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

A novel ambidentate dipeptide conjugate (H(L1)) containing N-donor atoms of the peptide part and an (O,O) chelate at the hydroxypyridinone (HP) ring is synthesized and characterized. It is hoped that this chelating ligand can be useful to obtain multitargeted Co(III)/Pt(II) dinuclear complexes with anticancer potential. The Pd(II) (as a Pt(II) model but with faster ligand exchange reactions) binding strength of the ligand was studied in an aqueous solution with the combined use of pH-potentiometry and NMR. In an equimolar solution, (L1)− was found to bind Pd(II) via the terminal amino and increasing number of peptide nitrogens of the peptide backbone over a wide pH range. At a 2:1 Pd(II) to ligand ratio, the presence of [Pd2H–x(L1)] (x = 1–4) species, with high stability and with the coordination of the (O,O) chelating set of the ligand, was detected. The reaction of H(L1) with [Co(tren)]3+ (tren = tris(2-aminoethyl)amine) indicated the exclusive binding of (L1)− via its (O,O) donor atoms to the metal unit, while treatment of the resulting Co-complex with Pd(II) afforded the formation of a Co/Pd heterobimetallic complex in solution with an (NH2, Namide) coordination of Pd(II). Shortening the peptide backbone in H(L1) by one peptide unit compared to the structurally similar ambidentate chelator consisting of three peptide bonds resulted in the slightly more favorable formation of the N-coordinated Pd(II) species, allowing the tailoring of the coordination properties.

25

Kaugarenia, Nastassia, Sophie Beaubier, Erwann Durand, Arnaud Aymes, Pierre Villeneuve, François Lesage, and Romain Kapel. "Optimization of Selective Hydrolysis of Cruciferins for Production of Potent Mineral Chelating Peptides and Napins Purification to Valorize Total Rapeseed Meal Proteins." Foods 11, no. 17 (August 29, 2022): 2618. http://dx.doi.org/10.3390/foods11172618.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Preventing oxidation and microbial spoilage are both major concerns in food industries. In this context, this study aimed to valorize the total rapeseed meal proteins with controlled enzymatic proteolysis to generate potent mineral-chelating peptides from cruciferins while keeping intact the antimicrobial napins. Implementation of proteolysis of total rapeseed protein isolate with the Prolyve® enzyme highlighted an interesting selective hydrolysis of the cruciferins. Hence, the mechanism of this particular hydrolysis was investigated through a Design of Experiments method to obtain a model for the prediction of kinetics (cruciferin degradation and napin purity) according to the operating conditions applied. Then, multicriteria optimization was implemented to maximize the napin purity and yield while minimizing both enzymatic cost and reaction time. Antioxidant assays of the peptide fraction obtained under the optimal conditions proved the high metal-chelating activity preservation (EC50 = 247 ± 27 µg) for more than three times faster production. This fraction might counteract lipid oxidation or serve as preventing agents for micronutrient deficiencies, and the resulting purified napins may have applications in food safety against microbial contamination. These results can greatly help the development of rapeseed meal applications in food industries.

26

Ibáñez, Alfredo J., Alexander Muck, and Aleš Svatoš. "Metal-Chelating Plastic MALDI (pMALDI) Chips for the Enhancement of Phosphorylated-Peptide/Protein Signals." Journal of Proteome Research 6, no. 9 (September 2007): 3842–48. http://dx.doi.org/10.1021/pr070243r.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Monney, Angèle, Flavia Nastri, and Martin Albrecht. "Peptide-tethered monodentate and chelating histidylidene metal complexes: synthesis and application in catalytic hydrosilylation." Dalton Transactions 42, no. 16 (2013): 5655. http://dx.doi.org/10.1039/c3dt50424g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Carrasco-Castilla, Janet, Alan Javier Hernández-Álvarez, Cristian Jiménez-Martínez, Carmen Jacinto-Hernández, Manuel Alaiz, Julio Girón-Calle, Javier Vioque, and Gloria Dávila-Ortiz. "Antioxidant and metal chelating activities of peptide fractions from phaseolin and bean protein hydrolysates." Food Chemistry 135, no. 3 (December 2012): 1789–95. http://dx.doi.org/10.1016/j.foodchem.2012.06.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Manhiani, Paljinder, Julie K. Northcutt, and Paul L. Dawson. "Comparative Study of Antioxidant Activity between Carnosine and Its Amino Acid Constituents." Journal of Food Research 12, no. 3 (July 14, 2023): 69. http://dx.doi.org/10.5539/jfr.v12n3p69.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

A study was conducted to compare and analyze the antioxidant mechanism of carnosine to its constituent amino acids (β-alanine and L-histidine) and to imidazole. Concentrations ranging from 5 to 100 mM of carnosine, β-alanine, L-histidine and imidazole were prepared and antioxidant activity assays (TBARS inhibition, metal chelating activity, free radical scavenging activity) were conducted. The TBARS inhibition of carnosine was due to the imidazole ring present in the histidine and with no inhibition contributed to β-alanine. Metal chelating properties of carnosine was also due to the imidazole ring and not to histidine or β-alanine, while free radical scavenging activity of carnosine was attributed to histidine and not due to imidazole or β-alanine. Overall, results demonstrate that β-alanine and the peptide bond between L- histidine and β-alanine do not play a role in the antioxidant activity of carnosine. Furthermore, results show that  imidazole has antioxidant properties alone, and therefore, it could be used as an antioxidant in various foods and feed applications.

30

Csire, Gizella, Laetitia Canabady-Rochelle, Marie-Christine Averlant-Petit, Katalin Selmeczi, and Loic Stefan. "Both metal-chelating and free radical-scavenging synthetic pentapeptides as efficient inhibitors of reactive oxygen species generation." Metallomics 12, no. 8 (2020): 1220–29. http://dx.doi.org/10.1039/d0mt00103a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Floresta, Giuseppe, George P. Keeling, Siham Memdouh, Levente K. Meszaros, Rafael T. M. de Rosales, and Vincenzo Abbate. "NHS-Functionalized THP Derivative for Efficient Synthesis of Kit-Based Precursors for 68Ga Labeled PET Probes." Biomedicines 9, no. 4 (April 1, 2021): 367. http://dx.doi.org/10.3390/biomedicines9040367.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Hexadentate tris(3,4-hydroxypyridinone) ligands (THP) complex Fe3+ at very low iron concentrations and their high affinities for oxophilic trivalent metal ions have led to their development for new applications as bifunctional chelators for the radiometal gallium-68 (68Ga). THP-peptide bioconjugates rapidly and quantitatively complex 68Ga at room temperature, neutral pH, and micromolar ligand concentrations, making them amenable to kit-based radiosynthesis of 68Ga PET radiopharmaceuticals. With the aim to produce an N-hydroxysuccinimide-(NHS)-THP reagent for kit-based 68Ga-labeling and PET imaging, THP-derivatives were designed and synthesized to exploit the advantages of NHS chemistry for coupling with peptides, proteins, and antibodies. The more stable five-carbon atoms linker product was selected for a proof-of-concept conjugation and radiolabeling study with an anti-programmed death ligand 1 (PD-L1) camelid single domain antibody (sdAb) under mild conditions and further evaluated for site-specific amide bond formation with a synthesized glucagon-like peptide-1 (GLP-1) targeting peptide using solid-phase synthesis. The obtained THP-GLP-1 conjugate was tested for its 68Ga chelating ability, demonstrating to be a promising candidate for the detection and monitoring of GLP-1 aberrant malignancies. The obtained sdAb-THP conjugate was radiolabeled with 68Ga under mild conditions, providing sufficient labeling yields after 5 min, demonstrating that the novel NHS-THP bifunctional chelator can be widely used to easily conjugate the THP moiety to different targeting molecules (e.g., antibodies, anticalins, or peptides) under mild conditions, paving the way to the synthesis of different imaging probes with all the advantages of THP radiochemistry.

32

Kjærgaard, Kristian, Jack K. Sørensen, Mark A. Schembri, and Per Klemm. "Sequestration of Zinc Oxide by Fimbrial Designer Chelators." Applied and Environmental Microbiology 66, no. 1 (January 1, 2000): 10–14. http://dx.doi.org/10.1128/aem.66.1.10-14.2000.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACT Type 1 fimbriae are surface organelles of Escherichia coli. By engineering a structural component of the fimbriae, FimH, to display a random peptide library, we were able to isolate metal-chelating bacteria. A library consisting of 4 × 107 independent clones was screened for binding to ZnO. Sequences responsible for ZnO adherence were identified, and distinct binding motifs were characterized. The sequences selected exhibited various degrees of affinity and specificity towards ZnO. Competitive binding experiments revealed that the sequences recognized only the oxide form of Zn. Interestingly, one of the inserts exhibited significant homology to a specific sequence in a putative zinc-containing helicase, which suggests that searches such as this one may aid in identifying binding motifs in nature. The zinc-binding bacteria might have a use in detoxification of metal-polluted water.

33

ZHANG, Fang L., and Patrick J. CASEY. "Influence of metal ions on substrate binding and catalytic activity of mammalian protein geranylgeranyltransferase type-I." Biochemical Journal 320, no. 3 (December 15, 1996): 925–32. http://dx.doi.org/10.1042/bj3200925.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Protein geranylgeranyltransferase type-I (GGTase-I) transfers a geranylgeranyl group from the prenyl donor geranylgeranyl diphosphate (GGPP) to the cysteine residue of substrate proteins containing a C-terminal CaaX-motif (a sequence motif of proteins consisting of an invariant Cys residue fourth from the C-terminus). The GGTase-I heterodimer contains one atom of zinc, and this metal is required for enzyme activity. In this regard, GGTase-I is similar to the related enzyme protein farnesyltransferase (FTase); the latter enzyme also requires Mg2+ for activity. The current studies were undertaken in an attempt to explore further the role of bivalent metal ions in the activity of GGTase-I. Surprisingly, we found that GGTase-I and FTase have different metal requirements. Specifically, in marked contrast to FTase, GGTase-I does not require Mg2+ for activity. Direct binding assays, including a novel fluorescence-based technique, were employed to obtain quantitative information on the interaction of substrates with GGTase-I. Using these assays, we demonstrate that the Zn2+ in GGTase-I is required for peptide, but not for isoprenoid, substrate binding. Moreover, binding of GGPP protects GGTase-I from inactivation by zinc-chelating reagents; this protective effect is not seen with binding of peptide substrates. Metal substitution studies show that the Zn2+ in GGTase-I can be replaced by Cd2+, and that the Cd form of GGTase-I has altered specificity with regard to utilization of both peptide and isoprenoid substrates. The significance of these findings in relation to proposed mechanisms for the GGTase-I reaction is discussed.

34

Smith, M. C., T. C. Furman, T. D. Ingolia, and C. Pidgeon. "Chelating peptide-immobilized metal ion affinity chromatography. A new concept in affinity chromatography for recombinant proteins." Journal of Biological Chemistry 263, no. 15 (May 1988): 7211–15. http://dx.doi.org/10.1016/s0021-9258(18)68629-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Caragounis, Aphrodite, Tai Du, Gulay Filiz, Katrina M. Laughton, Irene Volitakis, Robyn A. Sharples, Robert A. Cherny, et al. "Differential modulation of Alzheimer's disease amyloid β-peptide accumulation by diverse classes of metal ligands." Biochemical Journal 407, no. 3 (October 12, 2007): 435–50. http://dx.doi.org/10.1042/bj20070579.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Biometals have an important role in AD (Alzheimer's disease) and metal ligands have been investigated as potential therapeutic agents for treatment of AD. In recent studies the 8HQ (8-hydroxyquinoline) derivative CQ (clioquinol) has shown promising results in animal models and small clinical trials; however, the actual mode of action in vivo is still being investigated. We previously reported that CQ–metal complexes up-regulated MMP (matrix metalloprotease) activity in vitro by activating PI3K (phosphoinositide 3-kinase) and JNK (c-jun N-terminal kinase), and that the increased MMP activity resulted in enhanced degradation of secreted Aβ (amyloid β) peptide. In the present study, we have further investigated the biochemical mechanisms by which metal ligands affect Aβ metabolism. To achieve this, we measured the effects of diverse metal ligands on cellular metal uptake and secreted Aβ levels in cell culture. We report that different classes of metal ligands including 8HQ and phenanthroline derivatives and the sulfur compound PDTC (pyrrolidine dithiocarbamate) elevated cellular metal levels (copper and zinc), and resulted in substantial loss of secreted Aβ. Generally, the ability to inhibit Aβ levels correlated with a higher lipid solubility of the ligands and their capacity to increase metal uptake. However, we also identified several ligands that potently inhibited Aβ levels while only inducing minimal change to cellular metal levels. Metal ligands that inhibited Aβ levels [e.g. CQ, 8HQ, NC (neocuproine), 1,10-phenanthroline and PDTC] induced metal-dependent activation of PI3K and JNK, resulting in JNK-mediated up-regulation of metalloprotease activity and subsequent loss of secreted Aβ. The findings in the present study show that diverse metal ligands with high lipid solubility can elevate cellular metal levels resulting in metalloprotease-dependent inhibition of Aβ. Given that a structurally diverse array of ligands was assessed, the results are consistent with the effects being due to metal transport rather than the chelating ligand interacting directly with a receptor.

36

Nowak, J., and H. Tsai. "The yeast aminopeptidase Y." Canadian Journal of Microbiology 34, no. 2 (February 1, 1988): 118–24. http://dx.doi.org/10.1139/m88-024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

A metal-dependent aminopeptidase (EC 3.4.11.-), designated APase Y, has been purified to homogeneity by conventional methods. The enzyme is composed of a single polypeptide chain with molecular mass of 102 kilodaltons, estimated by sodium dodecyl sulphate – polyacrylamide gel electrophoresis, with a blocked N-terminal amino acid. It possesses neither endopeptidase nor carboxypeptidase activity and is strongly inhibited by metal-chelating agents, Zn2+, and the protein inhibitor from Neurospora crassa. APase Y is insensitive to Cl anions, S—S reducing reagents, serine protease inhibitors, and the peptidase inhibitor benzamidine. Co2+, Hg2+, and p-chloromercuribenzoate can activate the enzyme up to 22, 20, and 55%, respectively. The holoenzyme is resistant to yeast endopeptidases A, B, and Y, whereas the apoenzyme (obtained after treatment with chelators) is susceptible to the serine endopeptidases B and Y. The enzyme catalyzes hydrolysis of most L peptides possessing free α-amino (or imino) group by stepwise removal of N-terminal residue. Peptides with L-leucine at the N terminus are cleaved preferentially. The enzyme is unable to catalyze hydrolysis of X—Pro type peptide bonds, and inefficiently hydrolyzes bonds between Asp—X and Glu—X. L-leucine p-nitroanilide hydrolyzes optimally at pH 8.2 with a Km value of 1 mM. The purified enzyme is stable during storage in 0.05 M phosphate buffer, pH 6.7, containing 40–50% glycerol, at −20 °C.

37

Famuwagun, Akinsola A., Adeola M. Alashi, Saka O. Gbadamosi, Kehinde A. Taiwo, Durodoluwa Oyedele, Odunayo C. Adebooye, and Rotimi E. Aluko. "Effect of Protease Type and Peptide Size on the In Vitro Antioxidant, Antihypertensive and Anti-Diabetic Activities of Eggplant Leaf Protein Hydrolysates." Foods 10, no. 5 (May 18, 2021): 1112. http://dx.doi.org/10.3390/foods10051112.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Solanum macrocarpon (eggplant) leaf protein isolate (ELI) was hydrolyzed using four different enzymes to produce hydrolysates from alcalase (AH), chymotrypsin (CH) pepsin (PH) and trypsin (TH). CH had an overall stronger antioxidant property and was separated using ultrafiltration membranes into <1, 1–3 and 3–5 kDa peptide fractions. Gel-permeation chromatography confirmed conversion of the ELI (average of 22 kDa) into protein hydrolysates that contained smaller peptides (<6 kDa). A total of 23 peptides consisting of tri and tetrapeptides were identified from the CH, which is a wider spectrum when compared to seven for AH and four each for TH and PH. CH exhibited stronger scavenging activities against DPPH and hydroxyl radicals. CH and TH exhibited the strongest inhibitions against angiotensin-converting enzyme. In contrast, AH was the strongest inhibitor of α-amylase while AH and PH had strong inhibitory activities against α-glucosidase when compared with other hydrolysates. Ultrafiltration fractionation produced peptides that were stronger (p < 0.05) scavengers of DPPH, and hydroxyl radicals, in addition to better metal-chelating and enzyme inhibition agents. The study concluded that the eggplant protein hydrolysates and the UF fractions may find applications in tackling oxidative stress-related diseases and conditions involving excessive activities of the metabolic enzymes.

38

Ahmadi, Mahmoud Kamal, Samar Fawaz, Charles H. Jones, Guojian Zhang, and Blaine A. Pfeifer. "Total Biosynthesis and Diverse Applications of the Nonribosomal Peptide-Polyketide Siderophore Yersiniabactin." Applied and Environmental Microbiology 81, no. 16 (May 29, 2015): 5290–98. http://dx.doi.org/10.1128/aem.01373-15.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACTYersiniabactin (Ybt) is a mixed nonribosomal peptide-polyketide natural product natively produced by the pathogenYersinia pestis. The compound enables iron scavenging capabilities upon host infection and is biosynthesized by a nonribosomal peptide synthetase featuring a polyketide synthase module. This pathway has been engineered for expression and biosynthesis usingEscherichia colias a heterologous host. In the current work, the biosynthetic process for Ybt formation was improved through the incorporation of a dedicated step to eliminate the need for exogenous salicylate provision. When this improvement was made, the compound was tested in parallel applications that highlight the metal-chelating nature of the compound. In the first application, Ybt was assessed as a rust remover, demonstrating a capacity of ∼40% compared to a commercial removal agent and ∼20% relative to total removal capacity. The second application tested Ybt in removing copper from a variety of nonbiological and biological solution mixtures. Success across a variety of media indicates potential utility in diverse scenarios that include environmental and biomedical settings.

39

Kreutzer, Martin F., Hirokazu Kage, Peter Gebhardt, Barbara Wackler, Hans P. Saluz, Dirk Hoffmeister, and Markus Nett. "Biosynthesis of a Complex Yersiniabactin-Like Natural Product via themicLocus in Phytopathogen Ralstonia solanacearum." Applied and Environmental Microbiology 77, no. 17 (July 1, 2011): 6117–24. http://dx.doi.org/10.1128/aem.05198-11.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACTA genome mining study in the plant pathogenic bacteriumRalstonia solanacearumGMI1000 unveiled a polyketide synthase/nonribosomal peptide synthetase gene cluster putatively involved in siderophore biosynthesis. Insertional mutagenesis confirmed the respective locus to be operational under iron-deficient conditions and spurred the isolation of the associated natural product. Bioinformatic analyses of the gene cluster facilitated the structural characterization of this compound, which was subsequently identified as the antimycoplasma agent micacocidin. The metal-chelating properties of micacocidin were evaluated in competition experiments, and the cellular uptake of gallium-micacocidin complexes was demonstrated inR. solanacearumGMI1000, indicating a possible siderophore role. Comparative genomics revealed a conservation of the micacocidin gene cluster in defined, but globally dispersed phylotypes ofR. solanacearum.

40

Amoscato, Andrew A., Damon A. Prenovitz, and Michael T. Lotze. "Rapid Extracellular Degradation of Synthetic Class I Peptides by Human Dendritic Cells." Journal of Immunology 161, no. 8 (October 15, 1998): 4023–32. http://dx.doi.org/10.4049/jimmunol.161.8.4023.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Dendritic cells (DCs) effectively process exogenous and endogenous Ag and present peptide in the context of both class I and class II molecules. We have demonstrated that peripheral blood DCs efficiently degrade synthetic class I peptides at their cell surface within minutes as determined by analyzing DC supernatants by HPLC. Fragments were verified as bona fide cleavage products by direct sequencing using collision-induced dissociation tandem mass spectrometry. The predominant degradative activities were 1) not secreted but associated with activity at the plasma membrane, 2) ecto-orientated, 3) not induced by peptide-specific interactions, and 4) not associated with nonspecific uptake. Sequence analysis indicated that both N- and C-terminal as well as endoproteolytic events were occurring at the cell surface. The primary exoproteolytic event was identified as CD13 or CD13-like activity through inhibition studies and could be inhibited by ubiquitin and metal-chelating agents. Endoproteolytic events could be inhibited in the presence of DTT, but the precise nature of this enzyme is still undetermined. Compared with the starting monocyte population, DCs cultured in the presence of granulocyte-macrophage CSF/IL-4 exhibited the highest degradative rate (4.3 nmol/min), followed by cultured monocytes (2.9 nmol/min) and freshly isolated monocytes (1.0 nmol/min). In addition to increased enzymatic activity, a change in substrate specificity was noted. Results are discussed with respect to APC loading, and alternatives are offered for circumventing such degradation.

41

Fashakin, Olumide Oluwatoyosi, Pipat Tangjaidee, Kridsada Unban, Wannaporn Klangpetch, Tabkrich Khumsap, Korawan Sringarm, Saroat Rawdkuen, and Suphat Phongthai. "Isolation and Identification of Antioxidant Peptides Derived from Cricket (Gryllus bimaculatus) Protein Fractions." Insects 14, no. 8 (July 29, 2023): 674. http://dx.doi.org/10.3390/insects14080674.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Crickets contain high protein content that can be used to improve nutrition but are less exploited. This study was conducted to isolate different Cricket Protein Fractions including albumin, globulin, glutelin, and prolamin. All fractions were characterized and hydrolyzed by commercial enzymes. The results showed that the glutelin fractions had the highest extraction yields with 53.9 ± 2.12% (p < 0.05). Moreover, glutelin hydrolysate fraction prepared by Alcalase with a 16.35 ±0.29% hydrolysis degree was selected for further purification because of their high antioxidant activities, including ABTS radical-scavenging activity (0.44–0.55 µmol Trolox eq./g) and metal chelating activity (1721.99–1751.71 µmol EDTA eq./g). Two active fractions, GA-1 (<3 kDa) and GA-2 (<3 kDa), were collected from the consecutive purification of glutelin hydrolysates, which included processes such as membrane ultrafiltration and gel filtration. The fractions were analyzed by LC-MS/MS to obtain 10 peptides with 3–13 amino acids identified as TEAPLNPK, EVGA, KLL, TGNLPGAAHPLLL, AHLLT, LSPLYE, AGVL, VAAV, VAGL, and QLL with a molecular weight range of 359.23–721.37 Da in the two fractions. The amino acid sequence shows a prevalence of hydrophobic amino acids (50–100%) such as valine and leucine in the peptide chains, accounting for its high antioxidant activity. In conclusion, cricket glutelin hydrolysate prepared by Alcalase can serve as an alternative source of potent edible bioactive peptides in functional food products.

42

González-Ortega, Omar, and Roberto Guzmán. "Reversible Immobilization of Chelating Affinity Surfactants on Reversed Phase Adsorbents for Protein and Peptide Separations under Metal Affinity Chromatography." American Journal of Analytical Chemistry 05, no. 14 (2014): 932–44. http://dx.doi.org/10.4236/ajac.2014.514101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Sanz, Yolanda, and Fidel Toldrá. "Purification and Characterization of an Arginine Aminopeptidase from Lactobacillus sakei." Applied and Environmental Microbiology 68, no. 4 (April 2002): 1980–87. http://dx.doi.org/10.1128/aem.68.4.1980-1987.2002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACT An arginine aminopeptidase (EC 3.4.11.6) that exclusively hydrolyzes basic amino acids from the amino (N) termini of peptide substrates has been purified from Lactobacillus sakei. The purification procedure consisted of ammonium sulfate fractionation and three chromatographic steps, which included hydrophobic interaction, gel filtration, and anion-exchange chromatography. This procedure resulted in a recovery rate of 4.2% and a 500-fold increase in specific activity. The aminopeptidase appeared to be a trimeric enzyme with a molecular mass of 180 kDa. The activity was optimal at pH 5.0 and 37°C. The enzyme was inhibited by sulfhydryl group reagents and several divalent cations (Cu2+, Hg2+, and Zn2+) but was activated by reducing agents, metal-chelating agents, and sodium chloride. The enzyme showed a preference for arginine at the N termini of aminoacyl derivatives and peptides. The Km values for Arg-7-amido-4-methylcoumarin (AMC) and Lys-AMC were 15.9 and 26.0 μM, respectively. The nature of the amino acid residue at the C terminus of dipeptides has an effect on hydrolysis rates. The activity was maximal toward dipeptides with Arg, Lys, or Ala as the C-terminal residue. The properties of the purified enzyme, its potential function in the release of arginine, and its further metabolism are discussed because, as a whole, it could constitute a survival mechanism for L. sakei in the meat environment.

44

Furlan, M., R. Robles, and B. Lamie. "Partial purification and characterization of a protease from human plasma cleaving von Willebrand factor to fragments produced by in vivo proteolysis." Blood 87, no. 10 (May 15, 1996): 4223–34. http://dx.doi.org/10.1182/blood.v87.10.4223.bloodjournal87104223.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Proteolytic cleavage of von Willebrand factor (vWF) takes place in the circulating blood of healthy subjects and is increased in some patients with von Willebrand disease type 2A. The hemostatically active large vWF multimers are degraded to smaller less active forms. It has been suggested that the polypeptide subunit of vWF is cleaved at the peptide bond 842Tyr-843Met. We purified (approximately 10,000-fold) from human plasma a vWF-degrading protease, using chelating Sepharose, hydrophobic interaction chromatography, and gel filtration. The enzyme was found to be virtually absent in the platelet lysates obtained by repeated freezing and thawing. The proteolytic activity was associated with a high molecular weight protein (approximately 300 kD) as judged by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. vWF was resistant against the protease in a neutral buffer at physiological ionic strength but became degraded at low salt concentration or in the presence of 1 mol/L urea. No degradation of human fibrinogen, bovine serum albumin, of calf skin collagen by the purified protease was noted under the same experimental conditions. Proteolytic activity showed a pH optimum at 8 to 9 and was strongly inhibited by chelating agents, whereas only slow inhibition was observed with N-ethylmaleimide. There was no inhibition by iodoacetamide, leupeptin, or serine protease inhibitors. The best peptidyl diazomethyl ketone inhibitor was Z-Phe-Phe-CHN2. Activation by divalent metal ions was found to increase in the following order: Zn2+ approximately Cu2+ approximately CD2+ approximately Ni2+ approximately Co2+ <Mn2+ <Mg2+ <Ca2+ <Sr2+ <Ba2+. The observed properties of the vWF- degrading enzyme differ from those of all other hitherto described proteases. Purified vWF was incubated with the protease, and the degraded material subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis after disulfide reduction. The size, amino acid composition, and amino terminal sequence of the reduced fragments confirmed that the peptide bond 842Tyr-843Met had been cleaved, ie, the same bond that has been proposed to be cleaved in vivo.

45

Kreher, Ute, Leone Spiccia, and Milton T. W. Hearn. "Interactions between an amphipathic di‐histidine peptide and a metal affinity chromatographic resin derived from a bis (tacn)butane chelating ligand." Journal of Separation Science 42, no. 24 (November 12, 2019): 3631–39. http://dx.doi.org/10.1002/jssc.201900908.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Inoue, Hiroyuki, Osamu Takimura, Ken Kawaguchi, Teruhiko Nitoda, Hiroyuki Fuse, Katsuji Murakami, and Yukiho Yamaoka. "Tin-Carbon Cleavage of Organotin Compounds by Pyoverdine from Pseudomonas chlororaphis." Applied and Environmental Microbiology 69, no. 2 (February 2003): 878–83. http://dx.doi.org/10.1128/aem.69.2.878-883.2003.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACT The triphenyltin (TPT)-degrading bacterium Pseudomonas chlororaphis CNR15 produces extracellular yellow substances to degrade TPT. Three substances (F-I, F-IIa, and F-IIb) were purified, and their structural and catalytic properties were characterized. The primary structure of F-I was established using two-dimensional nuclear magnetic resonance techniques; the structure was identical to that of suc-pyoverdine from P. chlororaphis ATCC 9446, which is a peptide siderophore produced by fluorescent pseudomonads. Spectral and isoelectric-focusing analyses revealed that F-IIa and F-IIb were also pyoverdines, differing only in the acyl substituent attached to the chromophore part of F-I. Furthermore, we found that the fluorescent pseudomonads producing pyoverdines structurally different from F-I showed TPT degradation activity in the solid extracts of their culture supernatants. F-I and F-IIa degraded TPT to monophenyltin via diphenyltin (DPT) and degraded DPT and dibutyltin to monophenyltin and monobutyltin, respectively. The total amount of organotin metabolites produced by TPT degradation was nearly equivalent to that of the F-I added to the reaction mixture, whereas DPT degradation was not influenced by monophenyltin production. The TPT degradation activity of F-I was remarkably inhibited by the addition of metal ions chelated with pyoverdine. On the other hand, the activity of DPT was increased 13- and 8-fold by the addition of Cu2+ and Sn4+, respectively. These results suggest that metal-chelating ligands common to pyoverdines may play important roles in the Sn-C cleavage of organotin compounds in both the metal-free and metal-complexed states.

47

Shu, Guowei, Qian Zhang, He Chen, Hongchang Wan, and Hong Li. "Effect Of Five Proteases Including Alcalase, Flavourzyme, Papain, Proteinase K And Trypsin On Antioxidative Activities Of Casein Hydrolysate From Goat Milk." Acta Universitatis Cibiniensis. Series E: Food Technology 19, no. 2 (December 1, 2015): 65–74. http://dx.doi.org/10.1515/aucft-2015-0015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Oxidation was related to the pathogenesis of human diseases. Adequate intake of antioxidant activity of food can reduce the levels of free radicals, prevent lipid peroxidation, and help the body against diseases. In the paper, casein from goat milk was hydrolyzed by five commercial proteases, namely, Alcalase, flavourzyme, papain, proteinase K and trypsin. The antioxidant activities of casein hydrolysates were assessed by evaluating hydrolysis degree, DPPH radical-scavenging activity, metal-chelating activity and superoxide radical scavenging activity. The results showed as follows: the DH of proteinase K, Alcalase, and trypsin were higher significantly than those of papain and flavourzyme. The Fe2+-chelation activity and superoxide radical scavenging activity of casein hydrolysates from goat milk by Alcalase was higher than the others, the DPPH scavenging activities of casein hydrolysates by Alcalase and papain was higher than the others and the DPPH scavenging activities by Alcalase and papain had no significant diffierence (p<0.05), so the optimal proteinase for hydrolysis casein from goat milk to produce antioxidant peptide was Alcalase.

48

Remy, Sandrine, Raymond M. Reilly, Katherine Sheldon, and Jean Gariepy. "A New Radioligand for the Epidermal Growth Factor Receptor: 111In-Labeled Human Epidermal Growth Factor Derivatized with a Bifunctional Metal-Chelating Peptide." Bioconjugate Chemistry 6, no. 6 (November 1995): 683–90. http://dx.doi.org/10.1021/bc00036a004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Rémy, Sandrine, Raymond M. Reilly, Katherine Sheldon, and Jean Gariépy. "A New Radioligand for the Epidermal Growth Factor Receptor: 111In Labeled Human Epidermal Growth Factor Derivatized with a Bifunctional Metal-Chelating Peptide." Bioconjugate Chemistry 7, no. 6 (January 1996): 721. http://dx.doi.org/10.1021/bc9601885.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Monfregola, Luca, Michele Saviano, and Stefania De Luca. "Synthesis and Characterization of a Selective Alpha(v)Beta(3) Receptor Cyclic Peptide Antagonist Functionalized with a Chelating Group for Metal Labelling." International Journal of Peptide Research and Therapeutics 16, no. 1 (November 12, 2009): 1–5. http://dx.doi.org/10.1007/s10989-009-9195-y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Metal-Chelating Peptide'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles