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1
Paventi, Martino, Francis L. Chubb e John T. Edward. "Assisted hydrolysis of the nitrile group of 2-aminoadamantane-2-carbonitrile". Canadian Journal of Chemistry 65, n. 9 (1 settembre 1987): 2114–17. http://dx.doi.org/10.1139/v87-351.
Testo completoAbstract (sommario):
Attempts to hydrolyse the nitrile group of 2-aminoadamantane-2-carbonitrile by mineral acid or alkali have been unsuccessful. However, treatment of the aminonitrile with benzaldehyde in alkaline solution gives the benzal derivative of the α-aminoamide, readily hydrolysed to the α-aminoamide. Alternatively, benzoylation of the amino group followed by acid hydrolysis gives successively the α-benzamido acid and the α-amino acid. Possible mechanisms for these facilitated hydrolyses are advanced.
2
Kurbanova, Marina, e Svetlana Maslennikova. "Acid Hydrolysis of Casein". Foods and Raw Materials 2, n. 1 (26 maggio 2014): 27–30. http://dx.doi.org/10.12737/4124.
Testo completo
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Thanh Ngoc, Nguyen Thi. "INFLUENCES OF TECHOLOGICAL HYDROLYSIS CONDITION ON NUCLEIC ACID CONTENT OF SPENT BREWER’S YEAST HYDROLYSATE". Vietnam Journal of Science and Technology 55, n. 5A (24 marzo 2018): 169. http://dx.doi.org/10.15625/2525-2518/55/5a/12192.
Testo completoAbstract (sommario):
Currently, with the strong increasing of the brewing industry output, the consequencing amount of yeast residue is very large. Utilizing a large source of protein from brewers yeast to produce hydrolysed products using protease as food and food additives has a high real-life benefit. However, one limitation in the use of yeast and hydrolysis products is that the amount of nucleic acid in the yeast in particular and in the microbial cells is generally high. Nucleic acid is abundant in food that causes gout in humans and animals. There are many methods for reducing or separating nucleic acids in hydrolysed products such as extracellular ribonuclease enzymes, chemical agents, thermal shock and autolysis. Use extracellular ribonuclease enzyme for hydrolysis of nucleic acid gives good efficiency, but with high production cost. Chemical agents affect the quality of the hydrolysed products used in the food industry. There have been many good-efficiency studies using heat shock and autolysis to reduce the amount of nucleic acid in the hydrolysate. However, no research has been conducted to reduce the amount of nucleic acid by hydrolysis techniques. In this paper, we investigated the effects of heat shock, autolysis and hydrolysis techniques (batch, continuous overflow and continuous circulation) of brewery yeast protein to nucleic acid content in yeast hydrolysate. The results showed that the content of nucleic acid in the hydrolysate (with a concentration of 55 % dry matter) was the smallest. Under normal hydrolysis conditions, the nucleic acid content was 8.7 g / kg and when there was a heat shock+ autolysis, it decreased to 6.34 g/kg. After optimizing the hydrolysis conditions, the nucleic acid content of the hydrolysate was reduced to 5.41g/kg on continuous hydrolysis system.
4
Hendriks, W. H., M. F. Tarttelin e P. J. Moughan. "The amino acid composition of cat (Felis catus) hair". Animal Science 67, n. 1 (agosto 1998): 165–70. http://dx.doi.org/10.1017/s1357729800009905.
Testo completoAbstract (sommario):
AbstractThe amino acid composition of cat hair was determined by conventional 24-h acid hydrolysis and non-linear least-squares extrapolation to time zero of the amino acid composition data from a series of hydrolysis intervals. Twenty-five individual samples of cat hair, consisting of four colours, were also analysed (24-h hydrolysis) to determine if there was an effect of hair colour on amino acid composition. Amino acids were determined following HCl hydrolysis (6 mol/l) with cysteine and methionine determined by performic acid oxidation of the sample prior to hydrolysis.There was no significant (P > 0·05) effect of hair colour on the amino acid composition of cat hair. The non-linear compartmental model used to determine the amino acid composition of cat hair took into account the simultaneously occurring processes of hydrolysis and degradation of amino acids over time. The amino acids cysteic acid, methionine-sulphone, threonine and serine exhibited high loss rates during 6 molll HCl hydrolysis while the peptide bonds involving valine and leucine were slowly hydrolysed. Amino acid nitrogen accounted for 0·94 of the total nitrogen in cat hair when determined by conventional 24-h hydrolysis and 0·99 of the total nitrogen when the compartmental model was applied. The average nitrogen proportion in cat hair protein was found to be 0·175. The amino acid composition of cat hair protein is comparable with that of dog, horse, sheep and human hair although the proline content of cat hair protein appears to be lower than that in the other species.
5
Pęksa, A., e J. Miedzianka. "Amino acid composition of enzymatically hydrolysed potato protein preparations". Czech Journal of Food Sciences 32, No. 3 (11 giugno 2014): 265–72. http://dx.doi.org/10.17221/286/2013-cjfs.
Testo completoAbstract (sommario):
We determine the effects of the technology of obtaining potato protein preparation and of different variants of enzymatic hydrolysis on the chemical and amino acid compositions of the hydrolysates obtained. Potato protein concentrates obtained through their thermal coagulation in potato juice with calcium chloride, calcium lactate or without salt addition were subjected to enzymatic hydrolysis using two commercial hydrolytic enzymes: endopeptidase (Alcalase) and exopeptidase (Flavourzyme). Chemical (contents of ash, total and coagulable protein) and amino acid compositions of the hydrolysates obtained were determined. On the ground of the findings it was stated that the type of potato protein preparation used and conditions of enzymatic modification influenced on the properties of the hydrolysates obtained. Preparations obtained during the study were characterised by similar chemical and amino acid compositions, whereas the preparation obtained through thermal coagulation with the use of calcium lactate contained insignificantly more protein and essential amino acids. The least liable to enzymatic hydrolysis was the preparation obtained by using calcium chloride, particularly when only endopeptidase was used. The application of endopeptidase enzyme enabled to obtain 60% of proteolysis efficiency and the addition of the second enzyme (exopeptidase) to the protein solution insignificantly increased the proteolysis efficiency (to ca 70%), mainly when the preparation coagulated with the use of calcium chloride was hydrolysed. Proteolysis of the protein preparations obtained with the use of two enzymes was more favourable, particularly due to the quantity of free amino acids in and amino acids composition of the hydrolysates.
6
Lü, F., P. J. He, L. P. Hao e L. M. Shao. "Impact of recycled effluent on the hydrolysis during anaerobic digestion of vegetable and flower waste". Water Science and Technology 58, n. 8 (1 ottobre 2008): 1637–43. http://dx.doi.org/10.2166/wst.2008.511.
Testo completoAbstract (sommario):
Two trials were established to investigate the effect of recycled effluent on hydrolysis during anaerobic co-digestion of vegetable and flower waste. Trial I evaluated the effect by regulating the flow rate of recycled effluent, while Trial II regulated the ratio of hydrolytic effluent to methanogenic effluent, which were recycled to hydrolysis reactor. Results showed that the recirculation of methanogenic effluent could enhance the buffer capability and operation stability of hydrolysis reactor. Higher recycled flow rate was favourable for microbial anabolism and further promoted hydrolysis. After 9 days of hydrolysis, the cumulative SCOD in the hydrolytic effluent reached 334, 407, 413, 581 mg/g at recycled flow rates of 0.1, 0.5, 1.0, 2.0 m3/(m3·d), respectively. It was feasible to recycling a mixture of hydrolytic and methanogenic effluent to the hydrolysis reactor. This research showed that partially introducing hydrolytic effluent into the recycled liquid could enhance hydrolysis, while excessive recirculation of hydrolytic effluent will inhibit the hydrolysis. The flow ratio 1:3 of hydrolytic to methanogenic effluent was found to provide the highest hydrolysis efficiency and degradation rate of lignocelluloses-type biomass, among four ratios of 0:1, 1:3, 1:1 and 3:1. Under this regime, after 9 days of hydrolysis, the cumulative TOC and TN in the hydrolytic effluent reached 162 mg/g and 15 mg/g, the removal efficiency of TS, VS, C and cellulose in the solid phase were 60.66%, 62.88%, 58.35% and 49.12%, respectively. The flow ratio affected fermentation pathways, i.e. lower ratio favoured propionic acid fermentation and the generation of lactic acid while higher ratio promoted butyric acid fermentation.
7
Sinninghe Damsté, Jaap S., W. Irene C. Rijpstra, Ellen C. Hopmans, Johan W. H. Weijers, Bärbel U. Foesel, Jörg Overmann e Svetlana N. Dedysh. "13,16-Dimethyl Octacosanedioic Acid (iso-Diabolic Acid), a Common Membrane-Spanning Lipid of Acidobacteria Subdivisions 1 and 3". Applied and Environmental Microbiology 77, n. 12 (22 aprile 2011): 4147–54. http://dx.doi.org/10.1128/aem.00466-11.
Testo completoAbstract (sommario):
ABSTRACTThe distribution of membrane lipids of 17 different strains representing 13 species of subdivisions 1 and 3 of the phylumAcidobacteria, a highly diverse phylum of theBacteria, were examined by hydrolysis and gas chromatography-mass spectrometry (MS) and by high-performance liquid chromatography-MS of intact polar lipids. Upon both acid and base hydrolyses of total cell material, the uncommon membrane-spanning lipid 13,16-dimethyl octacosanedioic acid (iso-diabolic acid) was released in substantial amounts (22 to 43% of the total fatty acids) from all of the acidobacteria studied. This lipid has previously been encountered only in thermophilicThermoanaerobacterspecies but bears a structural resemblance to the alkyl chains of bacterial glycerol dialkyl glycerol tetraethers (GDGTs) that occur ubiquitously in peat and soil and are suspected to be produced by acidobacteria. As reported previously, most species also containediso-C15and C16:1ω7Cas major fatty acids but the presence ofiso-diabolic acid was unnoticed in previous studies, most probably because the complex lipid that contained this moiety was not extractable from the cells; it could only be released by hydrolysis. Direct analysis of intact polar lipids in the Bligh-Dyer extract of three acidobacterial strains, indeed, did not reveal any membrane-spanning lipids containingiso-diabolic acid. In 3 of the 17 strains, ether-boundiso-diabolic acid was detected after hydrolysis of the cells, including one branched GDGT containingiso-diabolic acid-derived alkyl chains. Since the GDGT distribution in soils is much more complex, branched GDGTs in soil likely also originate from other (acido)bacteria capable of biosynthesizing these components.
8
Zhuang, Jun Ping, Lu Lin, Chun Sheng Pang e Ying Liu. "Hydrolysis Kinetics of Wheat Straw in Saturated Formic Acid / 4% Hydrochloric Acid Solution". Advanced Materials Research 236-238 (maggio 2011): 138–41. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.138.
Testo completoAbstract (sommario):
Lignocellulosic materials are regarded as an alternative energy source for bioethanol production to reduce our reliance on fossil fuels. Pretreatment is an essential step in the enzymatic hydrolysis of biomass and subsequent production of bioethanol. Adding formic acid with catalyst dosage (4%) in saturated formic acid will be good for cellulose degradation and glucose production; when the cellulose hydrolyses to glucose, the glucose degrades simultaneously. Kinetic models can have practical applications for the optimization of the process and performance analysis, or economic estimations, so investigate the wheat straw hydrolysis kinetics is necessary. In this paper, effects of temperature and time on wheat straw hydrolysis in saturated formic acid with 4% hydrochloric acid solution reaction kinetics have been investigated. The results showed that the hydrolysis velocities of wheat straw were 0.0190 h−1at 60 °C, 0.0325 h−1at 65 °C, 0.0683 h−1at 70 °C and 0.0931 at 75 °C. The degradation velocities of glucose were 0.0285 h−1at 55 °C, 0.0448 h−1at 65 °C, 0.1098 h−1at 70°C and 0.1436 h−1at 75 °C. The activation energy of wheat straw hydrolysis was 106.35kJ/mol, and the activation energy of glucose degradation was 111.00kJ/mol.
9
Freeman, Stuart J., Prema Shankaran, Leonhard S. Wolfe e John W. Callahan. "Phosphatidylcholine and 4-methylumbelliferyl phosphorylcholine hydrolysis by purified placental sphingomyelinase". Canadian Journal of Biochemistry and Cell Biology 63, n. 4 (1 aprile 1985): 272–77. http://dx.doi.org/10.1139/o85-040.
Testo completoAbstract (sommario):
We present evidence which indicates that highly purified placental acid sphingomyelinase hydrolyses [14C]phosphatidylcholine ([14C]PC) and the synthetic phosphodiester 4-methylumbelliferyl phosphorylcholine (4-MUPC). Hydrolysis was achieved by phospholipase C phosphodiesterase action. Of the several detergents tested, sodium taurocholate alone was necessary for PC hydrolysis, while 4-MUPC was hydrolysed independent of any detergent requirement. The pH optima for the reactions were 4.6–4.8 for PC hydrolysis and 4.8–5.0 for 4-MUPC hydrolysis. As with sphingomyelin hydrolysis, degradation of both PC and 4-MUPC was inhibited by 5′-, 3′-, and 2′-AMP, 5′-AMP being the most effective of the three. Furthermore, the phosphodiesterase activity against PC and 4-MUPC copurified with sphingomyelinase from human placenta and cross-reacted with a specific anti-sphingomyelinase monoclonal antibody, strongly indicating identity of the phosphodiesterases. This explains phospholipase C deficiency in sphingomyelinase-deficient Niemann-Pick disease cells.
10
Loh, Zhi Hung, Natasha L. Hungerford, Diane Ouwerkerk, Athol V. Klieve e Mary T. Fletcher. "Identification of Acid Hydrolysis Metabolites of the Pimelea Toxin Simplexin for Targeted UPLC-MS/MS Analysis". Toxins 15, n. 9 (5 settembre 2023): 551. http://dx.doi.org/10.3390/toxins15090551.
Testo completoAbstract (sommario):
Pimelea poisoning of cattle is a unique Australian toxic condition caused by the daphnane orthoester simplexin present in native Pimelea pasture plants. Rumen microorganisms have been proposed to metabolise simplexin by enzymatic reactions, likely at the orthoester and epoxide moieties of simplexin, but a metabolic pathway has not been confirmed. This study aimed to investigate this metabolic pathway through the analysis of putative simplexin metabolites. Purified simplexin was hydrolysed with aqueous hydrochloric acid and sulfuric acid to produce target metabolites for UPLC-MS/MS analysis of fermentation fluid samples, bacterial isolate samples, and other biological samples. UPLC-MS/MS analysis identified predicted hydrolysed products from both acid hydrolysis procedures with MS breakdown of these putative products sharing high-resolution accurate mass (HRAM) fragmentation ions with simplexin. However, targeted UPLC-MS/MS analysis of the biological samples failed to detect the H2SO4 degradation products, suggesting that the rumen microorganisms were unable to produce similar simplexin degradation products at detectable levels, or that metabolites, once formed, were further metabolised. Overall, in vitro acid hydrolysis was able to hydrolyse simplexin at the orthoester and epoxide functionalities, but targeted UPLC-MS/MS analysis of biological samples did not detect any of the identified simplexin hydrolysis products.
11
KHUMALO, NDUDUZO, SAMSON MOHOMANE, SETUMO V. MOTLOUNG, LEHLOHONOLO KOAO, MALEVU D. THEMBINKOSI e TSHWAFO E. MOTAUNG. "EFFECT OF H2SO4/HCLO4 MIXTURE ON PROPERTIES OF SUGARCANE BAGASSE CELLULOSE CRYSTALS". WOOD RESEARCH 67(6) 2022 67, n. 6 (13 dicembre 2022): 929–40. http://dx.doi.org/10.37763/wr.1336-4561/67.6.929940.
Testo completoAbstract (sommario):
The main objective of the study was to investigate the effect of mixed acid concentration on the morphology, crystallinity and thermal properties of cellulose nanocrystals (CNCs). Acid hydrolysis using mixture of sulphuric (H2SO4)acid and perchloric (HClO4) acid was used to extract CNCs from sugarcane bagasse (SCB). The properties of the raw SCB, extracted cellulose,45% H2SO4 hydrolysed CNCs,45% H2SO4/HClO4 hydrolysed CNCs, 55% H2SO4/HClO4 hydrolysed CNCs and 65% H2SO4/HClO4 hydrolysed CNCs were analysed using Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Thecrystallinity of SCB was significantly increased after bleaching and acid hydrolysis. Acid hydrolysis using 55% H2SO4/HClO4 showed the highest crystallinity. The TGA results showed significant increase in thermal stability of 55% H2SO4/HClO4. The lowest thermal stability was observed with 45% H2SO4 hydrolysed CNCs. The order of thermal stability was raw SCB < extracted cellulose < 45% H2SO4hydrolysed CNCs < 65% H2SO4/HClO4 hydrolysed CNCs < 45% H2SO4/HClO4 hydrolysed CNCs < 55% H2SO4/HClO4 hydrolysed CNCs. The SEM results showed fibre breakage for 65% H2SO4/HClO4 hydrolysed CNCs. Thefibre breakage seemed to be acid concentration dependent.
12
Lisak Jakopović, Katarina, Seronei Chelulei Cheison, Ulrich Kulozik e Rajka Božanić. "Comparison of selective hydrolysis of α-lactalbumin by acid Protease A and Protease M as alternative to pepsin: potential for β-lactoglobulin purification in whey proteins". Journal of Dairy Research 86, n. 1 (febbraio 2019): 114–19. http://dx.doi.org/10.1017/s0022029919000086.
Testo completoAbstract (sommario):
AbstractThe experiments reported in this research paper examine the potential of digestion using acidic enzymes Protease A and Protease M to selectively hydrolyse α-lactalbumin (α-La) whilst leaving β-lactoglobulin (β-Lg) relatively intact. Both enzymes were compared with pepsin hydrolysis since its selectivity to different whey proteins is known. Analysis of the hydrolysis environment showed that the pH and temperature play a significant role in determining the best conditions for achievement of hydrolysis, irrespective of which enzyme was used. Whey protein isolate (WPI) was hydrolysed using pepsin, Acid Protease A and Protease M by randomized hydrolysis conditions. Reversed-phase high performance liquid chromatography was used to analyse residual proteins. Regarding enzyme selectivity under various milieu conditions, all three enzymes showed similarities in the reaction progress and their potential for β-Lg isolation.
13
Ying, Ma, Lin Li e Sun Da-Wen. "Preparation of high Fischer ratio oligopeptide by proteolysis of corn gluten meal". Czech Journal of Food Sciences 26, No. 1 (19 febbraio 2008): 38–47. http://dx.doi.org/10.17221/1138-cjfs.
Testo completoAbstract (sommario):
A method to obtain an oligopeptide with high Fischer ratio is described. Corn gluten meal (CGM) was hydrolysed with Alcalase 2.4L using a two-step hydrolysis. In the first-step hydrolysis, the enzyme reaction conditions for hydrolysing CGM were optimised by using the orthogonal experimental design, while pH = 8.0, temperature = 55°C, enzyme to substrate ratio (3:97, w/w), and the substrate concentration = 5% were identified as the optimum conditions, under which up to 11.62% degree of hydrolysis (DH) could be obtained. The hydrolysate was then fractionated by ultrafiltration using a membrane with the molecular cutoff of over 10 kD at 20 kPa. For the second-step hydrolysis, the filtrate was adjusted to pH 6.0, then papain was added at 50°C and the mixture was maintained for 3 hours. The hydrolysate was obtained after inactivating papain and centrifuging. Then the salt (mainly NaCl) in the hydrolysate was removed with an ion exchange resin at the speed of 8 times bed volume per hour, and aromatic amino acids were removed through absorption by active carbon. By using Sephadex G-25 gel filtration chromatography, a peptide mixture with low molecular weights between 1000 and 1300 was obtained. Finally, tests on amino acid composition and free amino acid concentration of oligopeptide solution showed that the oligopeptide had a high Fischer ratio of 34.71 and the yield of 11.59%.
14
Jassim, Khalid N. "Microwave-assisted acid and base pre-treatment of cellulose hydrolysis". Al Mustansiriyah Journal of Pharmaceutical Sciences 13, n. 2 (1 dicembre 2013): 16–21. http://dx.doi.org/10.32947/ajps.v13i2.196.
Testo completoAbstract (sommario):
The objective of this study is to hydrolysis the cellulose to glucose. The dilute acid and base hydrolysis of cellulose with hydrochloric, sulfuric acids sodium hydroxide and potassium hydroxide were undertaken alone, The conditions for the dilute acid and base hydrolysis were found to be 5% for both acids and bases at a temperature of 170°C and time 2 hours.It was found that the glucose yield by acid hydrolysis was 7.8% and by basehydrolysis was 8% .Then the dilute acid hydrolysis of cellulose with hydrochloric & sulfuric acids and the dilute base hydrolysis of cellulose with sodium and potassium hydroxide were undertaken in microwave oven for ten minutes only.The experimental data indicate that the use of microwave technology can successfully facilitate dilute acid hydrolysis and the dilute base hydrolysis of cellulose allowing high yields of glucose in short reaction times.These conditions gave a yield of 57% and 58% glucose by acids and base hydrolysis respectively. The microwave is the promising way to increase the glucose yield from cellulose
15
NAGY, Elena Mihaela, Constantin COȚA, Nicolae CIOICA, Zoltan GYORGY, Lucian FECHETE-TUTUNARU, Adina GHIRIŞAN e Vasile MICLĂUŞ. "Researches Regarding a Protein Hydrolysate Used as Adjuvant in Fertilization Process". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 76, n. 2 (18 novembre 2019): 78. http://dx.doi.org/10.15835/buasvmcn-agr:2018.0035.
Testo completoAbstract (sommario):
Within the paper the results of conducted researches in order to obtain a protein hydrolysate from wool waste as raw material are presented. The experiments were conducted in two variants: a) alkaline hydrolyse using potassium hydroxide, a mix of potassium hydroxide with urea and a mix of potassium hydroxide with sodium hydroxide as well as b) acidic hydrolyse with sulfuric acid or a mix of sufuric acid with phosphoric acid in different proportions. The parameters intervals used were: pH 0,5-2,5 for acidic hydrolyse and pH 9,5-13,5 for the alkalinic one; temperatures between 120-150 °C and pressures between 1,4-4,6 bar. Acid hydrolysis is favored by the high proportion of sulfuric acid, phosphoric acid, a low pH and from high temperature and pressure. The alkaline hydrolysis is favored by a pH higher then 12 as well as the urea content. A high temperature and pressure has a beneficial effect over alkaline hydrolysis.
16
Ab Rahim, Siti Kartini Enche, Heymmela A. P. Kasi e Norazharuddin Shah Abdullah. "Fermentable Sugar via Diluted Acid Hydrolysis of Sugarcane Bagasse". Key Engineering Materials 908 (28 gennaio 2022): 435–40. http://dx.doi.org/10.4028/p-75n3we.
Testo completoAbstract (sommario):
The production of fermentable sugar from sugarcane bagasse acid hydrolysis method was investigated in this study. Experimentation on the determination of acid for hydrolysis was carried out to identify the suitable type of acid for the effective hydrolysis process. The results revealed that sulphuric acid (H2SO4) is a better hydrolysing agent than phosphoric acid (H3PO4). This study also analysed the impact of temperature, on the yield of fermentable sugar between the sugarcane bagasse. The highest amount of fermentable sugar of 10.26 g/L was produced by sugarcane bagasse at temperature of 90°C, acid concentration of 4% (w/v) and a reaction time of 3 hours.
17
Jacobsen, Tomas, e Otto M. Poulsen. "Separation and characterization of 61- and 57-kDa lipases from Geotrichum candidum ATCC 66592". Canadian Journal of Microbiology 38, n. 1 (1 gennaio 1992): 75–80. http://dx.doi.org/10.1139/m92-012.
Testo completoAbstract (sommario):
Two lipolytic proteins (61 and 57 kDa) present in a Sephadex G-100 fraction of extracellular lipase from Geotrichum candidum ATCC 66592 were separated using high-performance liquid chromatography. Crossed electrofocusing immunoelectrophoresis was used to demonstrate that the 61-kDa lipase fraction contained two forms of lipase with pI 4.5 and 4.7. However, when deglycosylated with endoglycosidase H, the two forms gained an identical pI, 4.6. The 57-kDa lipase fraction contained one form of lipase with pI close to 4.5. Although the 61- and 57-kDa lipases were immunologically identical, the substrate specificity differed. Thus, the 61-kDa lipase hydrolysed palmitic acid methyl ester at an initial velocity of hydrolysis that was 60% of the initial velocity of hydrolysis of oleic acid methyl ester, whereas the 57-kDa lipase hydrolysed palmitic acid methyl ester at an initial velocity of hydrolysis that was only7% of the initial velocity of hydrolysis of oleic acid methyl ester. Key words: Geotrichum candidum, lipases, multiple forms, deglycosylation, substrate specificity.
18
Appel, Thomas R., Ralf Lucassen, Martin H. Groschup, Marion Joncic, Michael Beekes e Detlev Riesner. "Acid inactivation of prions: efficient at elevated temperature or high acid concentration". Journal of General Virology 87, n. 5 (1 maggio 2006): 1385–94. http://dx.doi.org/10.1099/vir.0.81426-0.
Testo completoAbstract (sommario):
Scrapie prion rods isolated from hamster and non-infectious aggregates of the corresponding recombinant protein rPrP(90–231) were incubated with hydrochloric acid. The amount of PrP and of infectivity that survived incubation in HCl at varying times, acid concentrations and temperatures was quantified by Western blot densitometry and bioassays, respectively. Prion rods and rPrP aggregates showed similar HCl hydrolysis kinetics of PrP, indicating structural homology. For 1 M HCl and 25 °C, the rate of PrP hydrolysis follows first-order kinetics at 0·014 h−1; the rate of infectivity inactivation is 0·54 h−1. Hydrolysis for 1 h at 25 °C was only slightly proportional to HCl concentration up to 5 M, but complete loss of infectivity and PrP reduction to <2 % was observed at 8 M HCl. The temperature dependence of unhydrolysed PrP, as well as infectivity at 1 M HCl for 1 h, showed a slight decrease up to 45 °C, but a sigmoidal decrease by several orders of magnitude at higher temperatures. The slow hydrolysis of PrP and inactivation of infectivity by acid treatment at room temperature are attributed to solvent inaccessibility of prion rods and rPrP aggregates, respectively. The more effective hydrolysis and inactivation at temperatures above 45 °C are interpreted as thermally induced disaggregation with an activation energy of 50–60 kJ mol−1. Most importantly, infectivity was always inactivated faster or to a higher extent than PrP was hydrolysed at several incubation times, HCl concentrations and temperatures.
19
Magadova, L. A., A. N. Sirotin, M. D. Pakhomov e Z. R. Davletov. "Study of Hydrolization and Sedimantationin Acid Compositions Based on Sulfaminic Acid". Oil and Gas Technologies 130, n. 5 (2020): 32–37. http://dx.doi.org/10.32935/1815-2600-2020-130-5-32-37.
Testo completoAbstract (sommario):
This article presents the results of a study of the hydrolysis of sulfamic acid and the elaboration of acidic compositions that are characterized by reduced sedimentation compared to mud acid. The effect of complexing compounds on the hydrolysis of sulfamic acid is considered, the hydrolysis of sulfamic acid and sulfamates is compared, and the secondary sedimentation of sulfamic acid and mud acid compositions is compared using the formation of hexafluorosilicates. The hydrolysis intensity of sulfamic acid and ammonium sulfamate was determined by the mass of sediments formed during the reaction of hydrolysis products with calcium chloride. The mass of calcium sulfate formed is proportional to the rate of hydrolysis of sulfamic acid. The process of dissolution of the quartz component of the terrigenous formation was studied using the gravimetric method. Differences in influence of EDTA, HEDP, and NTP on sedimentation prevention of the products of sulfamic acid hydrolysis were studied by the example of reactions with Ca2+. It was shown that compositions with NTP are characterized by a lower sediments formation. The ratio of NTP concentration and the hydrolysis rate of sulfamic acid is shown. Differences in the hydrolysis rate of compositions based on sulfamic acid and sulfamates were determined at a temperature of 80°C. It was shown that sulfamates are characterized by a lower rate of hydrolysis. Differences in quartz solubility were determined for compositions based on sulfamic and sulfuric acids, differences in the reactions kinetics were shown. It has been established that acid compositions based on sulfamic acid are characterized by less sedimentation rate being compared with acid compositions based on hydrochloric acid by the example of hexafluorosilicates formation.
20
Bakhtiyarova, Anna V., Sergei D. Pimenov e Alexander I. Sizov. "Hydrolysis of Wood Hemicelluloses at Ultra-Low Sulfuric Acid Concentrations". Lesnoy Zhurnal (Forestry Journal), n. 1 (10 febbraio 2023): 201–12. http://dx.doi.org/10.37482/0536-1036-2023-1-201-212.
Testo completoAbstract (sommario):
Studies in the field of hydrolysis of plant polysaccharides are ordinary classified according to protic reactions with diluted or concentrated acids. Such classification is based on the significant difference in the mechanisms of the reactions. The hydrolysis of polysaccharides of plant materials with the diluted acids is indicated by the concentrations of the mineral acids 0.5–10.0 % or happens by acid-free autohydrolysis, without any use of acids. Each of these reactions has considerably different kinetic and temperature-time parameters. They have both advantages and disadvantages. In particular, the hydrolysis using dilute acids is specified by a significant consumption of reagents and the presence of a large amount of carbohydrate degradation products in the hydrolysate. Autohydrolysis is characterized by a relatively low monosaccharide yield, high energy consumption for the process and the formation of many by-products. To date, studies regarding hydrolysis of polysaccharides of plant materials with acids in a concentration range of less than 0.5 % are absent. The reason for the lack of interest in research in this area, in our opinion, was the statement that acid in the process of hydrolysis is spent on the neutralization of ash components of plant materials at a flow rate of 5 to 20 g/kg of dry raw materials. Accordingly, when hydrolysis is carried out with ultra-low concentrations of acid, it is possible to completely neutralize it and switch the hydrolysis process from acid to acid-free autohydrolysis. The purpose of the work was to establish the efficiency of the hydrolysis process at ultra-low acid consumption. A study of the process of hydrolysis of hemicelluloses of birch wood at ultra-low concentrations of sulfuric acid was carried out. The possibility of almost complete hydrolysis of hemicelluloses with sulfuric acid with concentration of 0.10–0.25 % is shown. The process of hydrolysis of hemicelluloses with ultra-low acid concentrations is well described by the first order reaction. The general kinetic constants are calculated according to the experimental data. They show that the process occupies an intermediate position between acid-free autohydrolysis and traditional hydrolysis of hemicelluloses with sulfuric acid with a concentration of more than 0.5 %. The developed technique is advantageously different from the known methods of hydrolysis of hemicelluloses by low consumption of sulfuric acid (more than 5 times) and energy resources. Hemicellulose hydrolysates obtained by ultra-low acid concentration regimes have high benign properties and can be used in xylitol production.
21
Balasubramanian, R., e M. S. Manocha. "Purification and properties of an acid proteinase from Choanephora cucurbitarum". Canadian Journal of Microbiology 32, n. 2 (1 febbraio 1986): 151–55. http://dx.doi.org/10.1139/m86-030.
Testo completoAbstract (sommario):
An acid proteinase has been purified from mycelial extracts of Choanephora cucurbitarum by treatment with ammonium sulphate, gel filtration, hydroxyapatite adsorption, and affinity chromatography. The enzyme hydrolysed haemoglobin rapidly compared with casein, bovine albumin, cytochrome c, and hide powder azure, but failed to hydrolyse any of the synthetic peptides tested. The acid proteinase is a glycoprotein with an apparent molecular weight of 12 700. Optimal hydrolysis of haemoglobin by the proteinase was observed at 20 °C, pH 3.0, and has a Km value of 2.8 mg∙mL−1. Heavy metallic ions, such as Hg2+, Fe2+, and Zn2+, inhibited the hydrolytic activity, whereas Ca2+ and Cu2+ enhanced the enzyme activity by two- and four-fold, respectively, as compared with the controls. Benzamidine and phenylmethanesulfonyl fluoride inhibited severely the enzyme activity, while diisopropyl fluorophosphate, antipain, N-α-p-tosyl-L-lysine chloromethyl ketone inhibited moderately. Phenylmethanesulfonyl fluoride inhibition could be reversed by 2-mercaptoethanol. Reducing agents such as cysteine and dithiothreitol did not enhance the enzyme activity. The data presented suggest that the enzyme has the characteristics of serine proteinases.
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Fitriani, Reni Okta, Amna Hartiati e Lutfi Suhendra. "KARAKTERISTIK GULA CAIR YANG DIBUAT DARI PATI UBI GADUNG (Dioscorea hispida D.) DALAM VARIASI JENIS DAN KONSENTRASI ASAM". JURNAL REKAYASA DAN MANAJEMEN AGROINDUSTRI 6, n. 3 (3 settembre 2018): 203. http://dx.doi.org/10.24843/jrma.2018.v06.i03.p03.
Testo completoAbstract (sommario):
This study aims to know the effect of acid type and concentration on the characteristics of liquid sugar resulting from the hydrolysis of yam gadung (Dioscorea hispida D.) and the highest DE value from the hydrolysis of the yam gadung starch. This research uses Randomized Block Design of factorial pattern. The first factor is acid treatment consisting of 3 levels: hydrolysis of starch with HNO3, H2SO4, and HCl and second factor is acid concentration consisting of 3 levels: 3%, 4%, and 5% . Each treatment is grouped into 2 based on execution time. The variables observed in this study were total sugar reduction, reducing sugar content, Dextrose Equivalent (DE), clarity, and total dissolved solids. The best treatment determination was done by analysis on DE value of hydrolysis result of yam gadung starch. The treatment of acid type variation was very significant and the acid concentration had a significant effect on the value of DE of hydrolysed yam gadung starch. The best hydrolysis treatment of starchy yam starch is by using chloride acid variation at 3% concentration with Dextrose Equifalent (DE) value of 41,22%.
Keywords : starch, yam gadung, hydrolysis, acid
23
Kuan, Dingyaw, Lingmei Dai, Dehua Liu, Hongjuan Liu e Wei Du. "Efficient Biodiesel Conversion from Microalgae Oil of Schizochytrium sp." Catalysts 9, n. 4 (6 aprile 2019): 341. http://dx.doi.org/10.3390/catal9040341.
Testo completoAbstract (sommario):
Abstract: Microalgae oil has been regarded as a promising feedstock for biodiesel production. However, microalgae oil usually contains some non-lipid components, such as pigments. Microalgae oil could be converted to biodiesel effectively with a two-step process to decrease the negative effect caused by by-product glycerol generated in traditional biodiesel production process. Firstly, microalgae oil was hydrolysed to free fatty acids (FFAs) and then FFAs were converted to methyl ester. In this study, the hydrolysis of microalgae oil from Schizochytrium sp. was systematically investigated and microalgae oil could be hydrolysed effectively to FFAs at both non-catalytic and acid-catalytic conditions. The hydrolysis degree of 97.5% was obtained under non-catalytic conditions of 220 °C and a water to oil ratio of 10:1 (w:w). The hydrolysis degree of 97.1% was obtained with the optimized sulphuric acid catalytic conditions of 95 °C, and a ratio of water to oil 3:1. The lipase Novozym435-mediated esterification with the hydrolysed FFAs was explored and a FAME (Fatty Acids Methyl Ester) yield of 95.1% was achieved. The conversion of different FFAs also was compared and the results indicated that lipase Novozym435-mediated methanolysis was effective for the preparation of biodiesel as well as poly unsaturated fatty acids (PUFAs).
24
Zhu, Chao, Zihui Meng, Wenjin Liu, Hongwei Ma, Jiarong Li, Tongtong Yang, Yang Liu, Ni Liu e Zhibin Xu. "Investigation on the hydrolytic mechanism of cucurbit[6]uril in alkaline solution". Royal Society Open Science 5, n. 5 (maggio 2018): 180038. http://dx.doi.org/10.1098/rsos.180038.
Testo completoAbstract (sommario):
The structure of cucurbit[6]uril (CB[6]), as a fascinating supramolecular receptor, is regarded as ‘indestructible’. Herein, we investigated the hydrolysis of CB[6] catalysed by alkali. Our results showed that CB[6] was easily hydrolysed in 30% NaOH at 160°C within 3 h. Separation and purification of hydrolytic products demonstrated the presence of NH 3 , CO 2 , HCOONa, glycine and hydantoic acid. Based on the studies of the hydrolysis of substances similar to CB[6] including 4,5-dihydroxyethyleneurea, glycoluril and glycoluril dimer, we proposed that a plausible reaction mechanism involved a Cannizzaro reaction, which is supported by HPLC, mass spectrometry data and previous reports. Further studies are dedicated towards a controlled hydrolysis of CB[6], which will provide a new route for direct functionalization of CB[6].
25
Ilalova, Guzel, Ruslan Safin, Shamil Mukhametzyanov e Albina Gazizullina. "Hydrolysis as a basis for processing vegetable waste into bioplastics". E3S Web of Conferences 221 (2020): 03009. http://dx.doi.org/10.1051/e3sconf/202022103009.
Testo completoAbstract (sommario):
The greening of processing waste from logging and woodworking industries involves measures to prevent the negative impact of production processes on the natural environment and is enabled by the development of resource-saving techniques that minimize harmful emissions to the environment. These production operations are based on hydrolytic cleavage of glycoside bonds of vegetable biomass polysaccharides with the formation of monosaccharides as the main reaction products. Despite the wide range of available methods of processing wood into promising materials (heat treatment, pyrolysis, hydrolysis, etc.), one of the most effective methods is to produce sugars by weak acids hydrolysis. In this regard, the paper describes the technology of high-temperature hydrolysis of pine sawdust with sulfurous acid in order to detect reducing substances (RS) in the hydrolysis residue. The paper considers the effect of sulfurous acid, temperature, and treatment time on the yield of RS.
26
Alvarez, Carlos, Manuel Rendueles e Mario Diaz. "The yield of peptides and amino acids following acid hydrolysis of haemoglobin from porcine blood". Animal Production Science 52, n. 5 (2012): 313. http://dx.doi.org/10.1071/an11218.
Testo completoAbstract (sommario):
Animal blood is the most important waste product from the meat industry due to the huge volumes produced and its pollutant power. Different methods are currently employed to process this by-product, such as drying, incineration or enzymatic hydrolysis. All these techniques are expensive, do not result in revalorisation or are not applicable at an industrial scale. In this paper, chemical hydrolysis is presented as an alternative to recover and increase the value of purified haemoglobin, the most abundant protein in blood. Non-enzymatic hydrolysis of haemoglobin is a good method for obtaining peptides due to its low cost, ease of control and the large amount of peptides produced, as well as being suitable for industrial applications. This paper presents a study of the use of two acids (sulfuric and hydrochloric) for this purpose under different experimental conditions. From the analysis of the kinetics of the hydrolysis process, four fractions can be defined: unbroken haemoglobin, soluble peptides, non-soluble peptides and free amino acids. A kinetic model was developed to simulate the hydrolysis mechanisms, providing a good fit to the experimental results. Both sulfuric and hydrochloric acid at concentrations of 6 M can hydrolyse the haemoglobin completely, but the average peptide size is lower for sulfuric than for hydrochloric acid.
27
Chen, Rui, Shengdong Zhu, Cunwu Chen, Bo Cheng, Jie Chen e Yuanxin Wu. "Reviving the Acid Hydrolysis Process of Lignocellulosic Material in Biorefinery". BioResources 9, n. 2 (4 febbraio 2014): 1824–27. http://dx.doi.org/10.15376/biores.9.2.1824-1827.
Testo completoAbstract (sommario):
The acid hydrolysis of lignocellulosic material (LM) is one of the most widely studied and important subprocess in the LM biorefinery. After acid hydrolysis, LM can be converted to various biofuels, biochemicals, and biomaterials through chemical or biochemical methods. However, conventional LM acid hydrolysis is not regarded as a cost-effective and environmentally-friendly process because it has drawbacks such as difficulties in acid recovery, equipment corrosion, and chemical wastes from the neutralization of acid and the removal of LM degradation products. Use of ionic liquids and solid acids during LM hydrolysis has provided potential technical tools to overcome these problems and has given new life to the LM acid hydrolysis process in the biorefinery. This editorial will discuss the role of the LM acid hydrolysis process in the LM biorefinery, provide an analysis of the conventional LM acid hydrolysis process, and briefly discuss new developments in the LM acid process.
28
KEROVUO, Janne, Juha ROUVINEN e Frank HATZACK. "Analysis of myo-inositol hexakisphosphate hydrolysis by Bacillus phytase: indication of a novel reaction mechanism". Biochemical Journal 352, n. 3 (8 dicembre 2000): 623–28. http://dx.doi.org/10.1042/bj3520623.
Testo completoAbstract (sommario):
Phytic acid (myo-inositol hexakisphosphate, InsP6) hydrolysis by Bacillus phytase (PhyC) was studied. The enzyme hydrolyses only three phosphates from phytic acid. Moreover, the enzyme seems to prefer the hydrolysis of every second phosphate over that of adjacent ones. Furthermore, it is very likely that the enzyme has two alternative pathways for the hydrolysis of phytic acid, resulting in two different myo-inositol trisphosphate end products: Ins(2,4,6)P3 and Ins(1,3,5)P3. These results, together with inhibition studies with fluoride, vanadate, substrate and a substrate analogue, indicate a reaction mechanism different from that of other phytases. By combining the data presented in this study with (1) structural information obtained from the crystal structure of Bacillus amyloliquefaciens phytase [Ha, Oh, Shin, Kim, Oh, Kim, Choi and Oh (2000) Nat. Struct. Biol. 7, 147Ő153], and (2) computer-modelling analyses of enzymeŐsubstrate complexes, a novel mode of phytic acid hydrolysis is proposed.
29
Darragh, Alison J., e Paul J. Moughan. "The Effect of Hydrolysis Time on Amino Acid Analysis". Journal of AOAC INTERNATIONAL 88, n. 3 (1 maggio 2005): 888–93. http://dx.doi.org/10.1093/jaoac/88.3.888.
Testo completoAbstract (sommario):
Abstract Determining the amino acid content of a protein involves the hydrolysis of that protein, usually in acid, until the protein-bound amino acids are released and made available for detection. Both the variability in the ease of peptide bond cleavage and differences in the acid stability of certain amino acids can significantly affect determination of a protein's amino acid content. By using multiple hydrolysis intervals, a greater degree of accuracy can be obtained in amino acid analysis. Correction factors derived by linear extrapolation of serial hydrolysis data are currently used. Compartmental modeling of the simultaneous hydrolysis (yield) and degradation (decay) of amino acids by nonlinear multiple regression of serial hydrolysis data has also been validated and applied to determine the amino acid composition of various biological samples, including egg-white lysozyme, human milk protein, and hair. Implicit in the routine application of serial hydrolysis in amino acid analysis, however, is an understanding that correction factors, derived either linearly or through the more accurate nonlinear multiple regression approach, need to be determined for individual proteins rather than be applied uniformly across all protein types.
30
Abbas, Khamis A., Phillip Hurst e John T. Edward. "Reexamination of the Kirkwood–Westheimer theory of electrostatic effects. V. Effect of charged substituents on the rates of alkaline hydrolysis of substituted strychnines". Canadian Journal of Chemistry 75, n. 4 (1 aprile 1997): 441–48. http://dx.doi.org/10.1139/v97-050.
Testo completoAbstract (sommario):
The rates of hydrolysis in aqueous sodium hydroxide of the alkaloid strychnine and seven of its derivatives have been determined at 50 and 75 °C. The kinetic data indicate that all the compounds, except strychninesulfoni acid-I, hydrolyze by competing second- and third-order mechanisms, involving one and two hydroxide ions, respectively; strychninesulfonic acid-I hydrolyzes by the second-order mechanism only. The quantitative effect of positively charged groups in enhancing, and negatively charged groups in depressing, the rates of hydrolysis is in rough agreement with calculations using Kirkwood–Westheimer theory. Keywords: Kirkwood–Westheimer theory; strychnine derivatives, hydrolysis of; lactams, hydrolysis of; electrostatic effects on rates of alkaline hydrolysis; alkaloids, reactions of.
31
Bassani, Andrea, Cecilia Fiorentini, Vellingiri Vadivel, Alessandro Moncalvo e Giorgia Spigno. "Implementation of Auto-Hydrolysis Process for the Recovery of Antioxidants and Cellulose from Wheat Straw". Applied Sciences 10, n. 17 (3 settembre 2020): 6112. http://dx.doi.org/10.3390/app10176112.
Testo completoAbstract (sommario):
Wheat straw is an easily affordable, cost-effective and natural source of antioxidants and cellulose, but its full potential is not yet utilized. In the present investigation, an auto-hydrolytic process was applied to recover both antioxidant phenolic compounds and cellulose from wheat straw. Two three-step acid/alkaline fractionation processes were applied differing for the first step: a conventional mild acid hydrolysis or an auto-hydrolysis. The liquors from the first step were analyzed for the recovery of antioxidants, while the final residues from the whole process were analyzed for cellulose yield and purity. The auto-hydrolysis process led to a higher yield in antioxidants but also in sugars (glucose and xylose) and sugar degradation products (5-HMF, 5-MF, furfural) than the acid hydrolysis process. The overall cellulose recovery (about 45% g/100 gcellulose wheat straw dm) and purity was comparable in the two processes; therefore, the auto-hydrolysis-based process could be recommended as a potentially more environmentally friendly process to recover antioxidants and cellulose from wheat straw for different applications. Finally, a first study on the optimization of hydrolysis step was provided from the point of view of improving the cellulose yield, monitoring the sugars release during both the acid hydrolysis and the auto-hydrolysis process.
32
Vanderfleet, Oriana M., Daniel A. Osorio e Emily D. Cranston. "Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, n. 2112 (25 dicembre 2017): 20170041. http://dx.doi.org/10.1098/rsta.2017.0041.
Testo completoAbstract (sommario):
Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238–475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes ‘design rules’ for CNCs with improved size uniformity and charge density. This article is part of a discussion meeting issue ‘New horizons for cellulose nanotechnology’.
33
Seyhan Ozturk, Seyhan Ozturk, Shahin Shahabi Shahin Shahabi e Halil Kutuk Halil Kutuk. "Kinetics and Mechanisms of Acid-Catalyzed Hydrolysis of Some N-(4-Substitutedaryl) Succinimide Compounds". Journal of the chemical society of pakistan 44, n. 2 (2022): 186. http://dx.doi.org/10.52568/000998/jcsp/44.02.2022.
Testo completoAbstract (sommario):
In this study, the mechanism of acid catalyzed hydrolysis of N-(4-substitutedaryl) succinimides in different acids was investigated. These acids are hydrochloric acid, perchloric acid and sulfuric acid, which were studied at 50.0and#177;0.1and#176;C. Analyses of the results obtained with the entropy of activation, Excess Acidity treatment and substituent effect are consistent across the entire acid studied by an A-2 mechanism. The catalytic order of strong acids for the acid catalyzed hydrolysis of the compounds studied were as HCl andgt; H2SO4 andgt; HClO4 in the whole range of acidity. This order is characteristics for an A–2 mechanism.
34
Badiani, K., X. Lu e G. Arthur. "Evidence for the regulation of guinea-pig heart microsomal phosphatidylcholine-hydrolysing phospholipase A1 by guanosine 5′-[γ-thio]triphosphate". Biochemical Journal 288, n. 3 (15 dicembre 1992): 965–68. http://dx.doi.org/10.1042/bj2880965.
Testo completoAbstract (sommario):
We have recently characterized lysophospholipase A2 activities in guinea-pig heart microsomes and postulated that these enzymes act sequentially with phospholipases A1 to release fatty acids selectively from phosphatidylcholine (PC) and phosphatidylethanolamine, thus providing an alternative route to the phospholipase A2 mode of release. In a further investigation of the postulated pathway, we have characterized the PC-hydrolysing phospholipase A1 in guinea-pig heart microsomes. Our results show that the enzyme may have a preference for substrates with C16:0 over C18:0 at the sn-1 position. In addition, although the enzyme cleaves the sn-1 fatty acid, the rate of hydrolysis of PC substrates with C16:0 at the sn-1 position was influenced by the nature of the fatty acid at the sn-2 position. The order of decreasing preference was C18:2 > C20:4 = C18:1 > C16:0. The hydrolyses of the molecular species were differentially affected by heating at 60 degrees C. An investigation into the effect of nucleotides on the activity of the enzyme showed that guanosine 5′-[gamma-thio]triphosphate (GTP[S]) inhibited the hydrolysis of PC by phospholipase A1 activity, whereas GTP, guanosine 5′-[beta-thio]diphosphate (GDP[S]), GDP, ATP and adenosine 5′-[gamma-thio]triphosphate (ATP[S]) did not affect the activity. The inhibitory effect of GTP[S] on phospholipase A1 activity was blocked by preincubation with GDP[S]. A differential effect of GTP[S] on the hydrolysis of different molecular species was also observed. Taken together, the results of this study suggest the presence of more than one phospholipase A1 in the microsomes with different substrate specificities, which act sequentially with lysophospholipase A2 to release linoleic or arachidonic acid selectively from PC under resting conditions. Upon stimulation and activation of the G-protein, the release of fatty acids would be inhibited.
35
Mujianto, ,., Yuli Witono, ,. Wignyanto, Sri Kumalaningsih e Auliani’am ,. "Hydrolysis Characteristics of Over Fermented Tempe (Fermented Soybean Cake) Product Hydrolyzed by Enzymatic Hydrolysis as Natural Flavor Source (Flavor Enhancer)". Indian Journal of Nutrition and Dietetics 55, n. 1 (12 gennaio 2018): 29. http://dx.doi.org/10.21048/ijnd.2018.55.1.18062.
Testo completoAbstract (sommario):
The purpose of this study is to be acknowledged of the characteristics of protein hydrolyzed from enzymatic hydrolysis process of rejected tempe. The parameters of rejected Tempe hydrolysis characteristics are dissoluble protein, dissoluble total sediment, maillard intensity, hydrolytic color, namely color L, color a, color b, whiteness, chrome and hue, level of staleness, antioxidant power, water activity, hydrolysis level, enzymatic reaction rate, HPLC amino acid and hydrolytic FTIR of over fermentedtempe. This study is designed using Randomized Complete Block Design with 3 (three) blocks as repetition. The result of this study indicates that the highest Hydrolysis Level (HL) belongs to Flavorzyme enzyme (10.3% HL), Protamex (8.4% HL) and Calontropin (7.1% HL) with enzymatic reaction rate for Flavorzyme enzyme is V max as much as 0.01727 mg per ml per minute, while the content of glutamate acid in hydrolyzed over fermented-tempe reaches 15.95%.
36
Firsty, Virginia Ghita, Ji Yeon Jeong, Yang Mo Gu, Jin Hyung Lee e Soo-Jeong Shin. "High Cellulose Purity by Acid Hydrolysis Pretreatment on Kenaf Outer Bast". Applied Sciences 13, n. 1 (27 dicembre 2022): 334. http://dx.doi.org/10.3390/app13010334.
Testo completoAbstract (sommario):
Acid hydrolysis treatment of kenaf outer bast fiber can produce pure cellulose content and hydrolyzed hemicellulose to monosaccharides. The effects of various reaction temperatures (110–130 °C), acid concentrations of sulfuric acid (0.25–1.00 N), and reaction times (60–120 min) were investigated as the optimum condition to gain pure cellulose content. A 1H NMR spectroscopy was used to analyze the carbohydrate content in the reaction of acid hydrolysis treatment. The results showed that optimum conditions for acid hydrolysis refer to two treatment prospects. First, a higher reaction temperature of 130 °C was necessary to increase the reaction for the hydrolyzes of hemicellulose—the high yield content produced by 0.25 N sulfuric acid with a short reaction time of 60 min. to improve the purity of cellulose, provided by the high sulfuric acid solution of 1.00 N for 120 min. Hemicellulose was hydrolyzed at almost 100% based on the two optimal conditions. The analysis revealed that a high temperature of acid hydrolysis was the primary treatment to hydrolyze hemicellulose to increase high pure cellulose from the kenaf outer bast fiber.
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Llames, Cynthia R., e Johannes Fontaine. "Determination of Amino Acids in Feeds: Collaborative Study". Journal of AOAC INTERNATIONAL 77, n. 6 (1 novembre 1994): 1362–402. http://dx.doi.org/10.1093/jaoac/77.6.1362.
Testo completoAbstract (sommario):
Abstract A total of 28 laboratories (including authors’ laboratories) participated in a collaborative study for determination of amino acids in feeds using 3 complementary procedures. Each collaborator analyzed 5 blind duplicate samples of feed and ingredients used in the poultry industry. The amount of amino acids in these materials ranged from 0.10 to 8.50%. Twenty-three laboratories conducted analyses using performic acid oxidation with acid hydrolysis—sodium metabisulfite method, 16 laboratories performed analyses using performic acid oxidation with acid hydrolysis—hydrobromic acid method, and 15 laboratories used acid hydrolysis method. The repeatability relative standard deviation values for all amino acids for all 3 procedures ranged from 1.1 to 5.6% for broiler finisher feed, 1.1 to 4.73% for starter feed, 1.3 to 9.6% for corn, 0.8 to 3.96% for fishmeal, and 0.8 to 12.7% for poultry meal. The reproducibility relative standard deviation values for all amino acids ranged from 3.71 to 19.80% for broiler finisher feed, 4.1 to 16.93% for starter feed, 4.4 to 28.2% for corn, 3.46 to 18.96% for fishmeal, and 3.73 to 24.1% for poultry meal. The performic acid oxidation with acid hydrolysis—sodium metabisulfite and hydrobromic acid methods, and acid hydrolysis method for determination of amino acids in feeds have been adopted first action by AOAC INTERNATIONAL.
38
Ibrahim, E. S. K., e M. A. Ghani. "The effect of enzymatic hydrolysis on the antioxidant activities and amino acid profiles of defatted chia (Salvia hispanica L.) flour". Food Research 4, S4 (6 dicembre 2020): 38–50. http://dx.doi.org/10.26656/fr.2017.4(s4).003.
Testo completoAbstract (sommario):
The aim of this study was to determine the effect of enzymatic hydrolysis using different proteases (Alcalase® and papain) and hydrolysis period on antioxidative activities and amino acid profiles of hydrolysed chia peptides. The experiment has been carried out using a completely randomized block design. The protein from defatted chia flour (DCF) was first isolated using different extraction pH (pH 10; 11; 12) and precipitation pH (pH 3.5, 4.0 and 4.5) to determine the highest protein isolated (CI) yield. The chia isolate (CI) extracted using the combination treatment (pH 12, 3.5) demonstrated the highest protein content of 17.22% and was selected to further hydrolysed using Alcalase® and papain enzyme at different hydrolysis time. The degree of hydrolysis (DH), protein solubility and peptide content of the chia protein hydrolysates (CH) were observed. Alcalase®-CH and Papain-CH demonstrated the highest DH at 60 mins of hydrolysis with the value of 47.09% and 44.29%, respectively. The protein solubility and peptide content were directly proportional to the DH. The Alcalase®-CH hydrolysed at 60 mins exhibited the highest antioxidant activities as measured by DPPH, ABTS and FRAP assays with values of 35.46µM AAE, 34.45µM TE and 23.11 µM FeSO4.7H2O E, respectively. The Alcalase®- CH demonstrated higher (p<0.05) hydrophobic amino acid (42.51%) compared to and Papain-CH (37.25%,). The highest aromatic amino acid content also recorded by Alcalase®-CH (20.10%), whereas Papain-CH with the value of 15.54%. However, both CH exhibited higher hydrophilic and aromatic amino acid compared to DCF and CI. This result has proved that the enzymatic hydrolysis of CH using Alcalase® and papain improved the nutritional and antioxidant capabilities, thus potentially represent a naturally occurring antioxidant ingredient in the production of functional food and nutraceutical appliance with significant health benefits.
39
Margolis, Sam A., Lois Jassie e H. M. Kingston. "The hydrolysis of proteins by microwave energy". Journal of Automatic Chemistry 13, n. 3 (1991): 93–95. http://dx.doi.org/10.1155/s1463924691000172.
Testo completoAbstract (sommario):
Microwave energy, at manually-adjusted, partial power settings has been used to hydrolyse bovine serum albumin at 125 °C. Hydrolysis was complete within 2 h, except for valine and isoleucine which were completely liberated within 4 h. The aminoacid destruction was less than that observed at similar hydrolysis conditions with other methods and complete hydrolysis was achieved more rapidly. These results provide a basis for automating the process of amino-acid hydrolysis.
40
ENGLISH, Denis, Margaret MARTIN, Kevin A. HARVEY, Luke P. AKARD, Ruth ALLEN, Theodore S. WIDLANSKI, Joe G. N. GARCIA e Rafat A. SIDDIQUI. "Characterization and purification of neutrophil ecto-phosphatidic acid phosphohydrolase". Biochemical Journal 324, n. 3 (15 giugno 1997): 941–50. http://dx.doi.org/10.1042/bj3240941.
Testo completoAbstract (sommario):
Phosphatidic acid and its derivatives play potentially important roles as extracellular messengers in biological systems. An ecto-phosphatidic acid phosphohydrolase (ecto-PAPase) has been identified which effectively regulates neutrophil responses to exogenous phosphatidic acid by converting the substrate to diacylglycerol. The present study was undertaken to characterize this ecto-enzyme on intact cells and to isolate the enzyme from solubilized neutrophil extracts. In the absence of detergent, short chain phosphatidic acids were hydrolysed most effectively by neutrophil plasma membrane ecto-PAPase; both saturated and unsaturated long chain phosphatidic acids were relatively resistant to hydrolysis. Both long (C18:1) and short (C8) chain lyso-phosphatidic acids were hydrolysed at rates comparable with those observed for short chain (diC8) phosphatidic acid. Activity of the ecto-enzyme accounted for essentially all of the N-ethylmaleimide-insensitive, Mg2+-independent PAPase activity recovered from disrupted neutrophils. At 37 °C and pH 7.2, the apparent Km for dioctanoyl phosphatidic acid (diC8PA) was 1.4×10-3 M. Other phosphatidic acids and lysophosphatidic acids inhibited hydrolysis of [32P]diC8PA in a rank order that correlated with competitor solubility, lysophosphatidic acids and unsaturated phosphatidic acids being much more effective inhibitors than long chain saturated phosphatidic acids. Dioleoyl (C18:1) phosphatidic acid was an unexpectedly strong inhibitor of activity, in comparison with its ability to act as a direct substrate in the absence of detergent. Other inhibitors of neutrophil ecto-PAPase included sphingosine, dimethyl- and dihydro-sphingosine, propranolol, NaF and MgCl2. Of several leucocyte populations isolated from human blood by FACS, including T cells, B cells, NK lymphocytes and monocytes, ecto-PAPase was most prevalent on neutrophils; erythrocytes were essentially devoid of activity. A non-hydrolysable, phosphonate analogue of phosphatidic acid, phosphonate 1, efficiently solubilized catalytic activity from intact neutrophils without causing cell disruption or increasing permeability. Enzyme activity in solubilized extracts was purified in the absence of detergent by successive heparin–Sepharose, gel filtration and anion exchange chromatography. By assaying activity in renatured SDS/polyacrylamide gel slices, the molecular mass of neutrophil ecto-PAPase was estimated to be between 45 and 52 kDa, similar to the molecular mass of previously purified plasma membrane PAPases. Since a large portion of neutrophil plasma membrane PAPase is available for hydrolysis of exogenous substrates, ecto-PAPase may play an important role in regulating inflammatory cell responses to extracellular phosphatidic acid in biological systems.
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Sugahara, Yasusato, e Akira Takahashi. "ACID HYDROLYSIS OF OXYCELLULOSE". Sen'i Gakkaishi 45, n. 6 (1989): 258–64. http://dx.doi.org/10.2115/fiber.45.6_258.
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Vårum, K. "Acid hydrolysis of chitosans". Carbohydrate Polymers 46, n. 1 (settembre 2001): 89–98. http://dx.doi.org/10.1016/s0144-8617(00)00288-5.
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Hilpmann, G., N. Becher, F. A. Pahner, B. Kusema, P. Mäki-Arvela, R. Lange, D. Yu Murzin e T. Salmi. "Acid hydrolysis of xylan". Catalysis Today 259 (gennaio 2016): 376–80. http://dx.doi.org/10.1016/j.cattod.2015.04.044.
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Vladimirova, M. V., I. A. Kulikov e A. A. Kuprii. "Trialkyl phosphate acid hydrolysis". Soviet Atomic Energy 70, n. 2 (febbraio 1991): 111–17. http://dx.doi.org/10.1007/bf01121851.
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Jankovská, P., J. Čopíková e A. Sinitsya. "The determination of ferulic acid in sugar beet pulp". Czech Journal of Food Sciences 19, No. 4 (9 febbraio 2013): 143–47. http://dx.doi.org/10.17221/6598-cjfs.
Testo completoAbstract (sommario):
The content of ferulic acid in sugar beet pulp was determined by reverse phase high-pressure liquid chromatography (HPLC) and UV/VIS-spectroscopy. The acid extracts of pectin carrying feruloyl groups were prepared for analysis. To release ferulic acid from pectin the hydrolysis in alkaline medium (pH = 12.5) was performed. Both non-hydrolysed and hydrolysed extracts were measured by UV/VIS-spectroscopy after pH adjustment to the value of 10. The absorbance maximum was observed at 372 nm (ester of ferulic acid) for non-hydrolysed extracts and at 345 nm (sodium ferulate) for hydrolysed extracts. The HPLC estimation of ferulic acid was made in hydrolysed extracts only. The content of ferulic acid in sugar beet pulp was in the range of 0.3–0.9% (m/m). The data obtained by application of the particular methods to one set of samples were statistically compared. The results of all methods were in good agreement with each other\
46
Gehrke, Charles W., Larry L. Wall, Joseph S. Absheer, Floyd E. Kaiser e Robert W. Zumwalt. "Sample Preparation for Chromatography of Amino Acids: Acid Hydrolysis of Proteins". Journal of AOAC INTERNATIONAL 68, n. 5 (1 settembre 1985): 811–21. http://dx.doi.org/10.1093/jaoac/68.5.811.
Testo completoAbstract (sommario):
Abstract A number of variations were evaluated in the techniques and procedures of the classical 6N hydrochloric acid, 110°C, 24 h hydrolysis of protein. Variations included the use of glass tubes with Teflon-lined screw caps as the hydrolysis vessel, high-temperature short-time hydrolysis, performic acid oxidation of cystine and methionine, multiple hydrolysis times at 145°C, and interlaboratory preparation of hydrolysates. A diverse sample set used in the study included a range of protein-containing matrices, and automated ionexchange chromatography was used for the amino acid analysis. Results show that for hydrolysis in glass tubes with Teflon-lined screw caps at 110°C for 24 h, recoveries of amino acids were in good agreement with recoveries by classical hydrolysis in sealed glass ampoules at reduced pressure. Recoveries from a higher temperature hydrolysis, i.e., 145°C for 4 h and using sealed ampoules, were also in agreement with 110°C, 24 h, sealed ampoule results; the former procedure yielded increased isoleucine and valine and decreased serine and threonine values. Glass tubes with Teflon-lined screw caps for hydrolysis were found to be a practical and convenient alternative to sealed glass ampoules; the improved precision with the former was probably due to the simplicity of the method. The average recovery of cystine from a wide range of matrices without the use of performic acid was 55.5% compared with results obtained with performic acid oxidation. Similarly, methionine is preferably analyzed as methionine sulfone. Interlaboratory evaluation of 145°C, 4 h hydrolysis, in which one laboratory used sealed ampoules and the other laboratory used Teflon-lined screw-cap tubes, demonstrated excellent agreement of amino acid values.
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Zumwalt, Robert W., Joseph S. Absheer, Floyd E. Kaiser e Charles W. Gehrke. "Acid Hydrolysis of Proteins for Chromatographic Analysis of Amino Acids". Journal of AOAC INTERNATIONAL 70, n. 1 (1 gennaio 1987): 147–51. http://dx.doi.org/10.1093/jaoac/70.1.147.
Testo completoAbstract (sommario):
Abstract The conditions used to hydrolyze proteins are vital in determining amino acid compositions because they necessarily represent a compromise aimed at yielding the best estimate of amino acid composition. Variations in ease of peptide bond cleavage, differences in amino acid stabilities, and matrix effects from nonproteinaceous components all militate against a single set of hydrolysis conditions that quantitatively hydrolyze every peptide bond and concurrently cause no destruction of any amino acid. This presentation summarizes and reviews an extensive study which evaluated a number of variations in the techniques and procedures of the classical 6N HC1, 110°C, 24 h hydrolysis of protein. The objectives of the recent investigation were: (/) to compare hydrolysis at 145°C, 4 h with 110°C, 24 h for proteins in a wide range of different sample matrixes; (2) to compare protein hydrolysis at 110°C, 24 h conducted in sealed glass ampoules after vacuum removal of air with hydrolysis in glass tubes with Teflon-lined screw caps after removal of air by vacuum, nitrogen purge, and sonication; (3) to evaluate a performic acid oxidation procedure before hydrolysis for the analysis of cystine and methionine in the different sample matrixes; (4) to evaluate multiple hydrolysis times at 145°C; (5) to evaluate the variation of interlaboratory hydrolysates prepared at 145°C, 4 h in 2 different laboratories on the amino acid analysis of an array of protein-containing matrixes. The major sources of inaccuracy and lack of precision arising from the application of ion-exchange or gas chromatography, both of which provide excellent accuracy and precision, are prechromatographic sample handling and the method used for hydrolysis of the protein sample itself. Hydrolysate preparation is the area that requires the most attention to solve problems of variability of amino acid analyses.
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Levy, Ryna, e Gene R. Herzberg. "Hydrolysis of long-chain, n-3 fatty acid enriched chylomicrons by cardiac lipoprotein lipase". Canadian Journal of Physiology and Pharmacology 77, n. 10 (15 ottobre 1999): 813–18. http://dx.doi.org/10.1139/y99-083.
Testo completoAbstract (sommario):
The hydrolysis of chylomicrons enriched in long-chain n-3 fatty acids by cardiac lipoprotein lipase was studied. In 60 min, 24.8% of the triacylglycerol fatty acids were released as free fatty acids. The fatty acids were hydrolyzed at different rates. DHA (docosahexaenoic acid, 22:6n-3) and EPA (eicosapentaenoic acid, 20:5n-3) were released at rates significantly less than average. Stearic acid (18:0), 20:1n-9, and alpha-linolenic acid (18:3n-3) were released significantly faster than average. There was no relationship between the rate of release of a fatty acid and the number of carbons or the number of double bonds. Lipoprotein lipase selectively hydrolyzes the fatty acids of chylomicron triacylglycerols. This selectively will result in remnants that are relatively depleted in 18:0, 20:1, and 18:3 and relatively enriched in 20:5 and 22:6.Key words: lipoprotein lipase, chylomicrons, fish oil, eicosapentaenoic acid, docosahexaenoic acid.
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Lumamuly, Vhindra Engson, Nikmans Hattu e Semuel Unwakoly. "ANALISIS KOMPONEN ASAM AMINO IKAN LAYANG DELES (Decapterus Makrosoma) HASIL OLAHAN TRADISIONAL BERDASARKAN LAMA PENYIMPANAN". Molluca Journal of Chemistry Education (MJoCE) 9, n. 2 (1 luglio 2019): 123–32. http://dx.doi.org/10.30598/mjocevol9iss2pp123-132.
Testo completoAbstract (sommario):
The aim of this study was to determine the amino acid composition of traditional processed Layang Deles fish (Decapterus macrosoma) which was stored for 2 months. Analysis of amino acid content using by Ultra Performance Liquid Chromatography (UPLC) instrument after content of water and lipid in sample was removed. The results of the analysis showed that there was a change in the concentration of 15 amino acids measured ranging from 85.17% to 2,873.42% in acid hydrolysis and 88.18% to 28.73% in alkaline hydrolysis. The biggest changes occurred in histidine, arginine and serine amino acid concentrations of 2,873.42%, 2,606.74% and 900.00% in acid hydrolysis and in amino acids serine, aspartic acid and histidine which were 88.17%, 62, 99% and 40.02% in alkaline hydrolysis. Based on the results of the research, it can be concluded that the processing of inmana fish with a storage period of 2 months affects the amino acid components of Layang Deles fish (Decapterus macrosoma).
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Kurniawan, Kurniawan, Susi Lestari e Siti Hanggita R. J. "HIDROLISIS PROTEIN TINTA CUMI-CUMI (Loligo sp) DENGAN ENZIM PAPAIN". Jurnal FishtecH 1, n. 1 (26 giugno 2014): 41–54. http://dx.doi.org/10.36706/fishtech.v1i1.796.
Testo completoAbstract (sommario):
The objective of this research were to know yield, protein content, free α-amino nitrogen, degree of hydrolysis, and amino acid of the result hydrolysis of ink protein squid (Loligo sp) with papain enzyme. The research used the method completely randomized design with two replications of the treatment factors, the difference in the concentration of the papain enzyme (0%, 1%, 2%, 3%, 4%, 5%, and 6%). The parameters of research were yield, protein content, free α-amino nitrogen, degree of hydrolysis, and amino acids. The results of research showed that differences in the concentration papain enzyme significant effect on the value of yield, protein content, free α-amino nitrogen, and degree of hydrolysis. Yield ranges from 78.05% to 88.61%, protein content from 28.90 mg/ml to 36.31 mg/ml, free α-amino nitrogen from 0.49 mg/ml to 10.99 mg/ml, the degree of hydrolysis from 0.016 to 0.345, and contains 14 kinds of amino acids of the 15 amino acids analyzed, histidine, arginine, threonine, valine, isoleucine, leucine, phenylalanine, lysine, glutamic acid, aspartic acid, serine, glycine, alanine, and tyrosine. The content of amino acid and degree of hydrolysis highest contained in the P2 treatment (papain enzyme concentration of 2%).