Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of dietary fiber viscosity on apparent ileal nitrogen and amino acid digestibility, proteolytic enzyme activity and digestive organ weights was investigated. Eighteen growing rats were fed for 21 d purified casein-based diets containing carboxymethylcellulose (50 g/kg) of low (20 cP), medium (800 cP) and high (2000 cP) viscosity (LV, MV and HV treatment groups, respectively). Dietary fiber viscosity did not significantly affect apparent ileal (terminal 15 cm of the ileum) nitrogen or amino acid digestibility, trypsin or chymotrypsin activity in the small intestinal contents and pancreatic tissue, aminopeptidase-N activity in the small intestinal contents and tissue, or the weights of the stomach, pancreas, small or large intestines. Intragastric pepsin activity in LV rats was significantly higher than in MV or HV rats (P < 0.01), but fiber viscosity did not affect pepsin activity in the stomach tissue. The intragastric pH of the HV and MV rats was significantly higher than that for the LV rats (P < 0.01). The stomach contents (dry matter) of MV and HV rats were greater than in LV rats (P < 0.05). Delayed passage rate of the more viscous digesta may have resulted in greater absorption of amino acids, because the HV rats had a higher estimated true ileal digestibility than the LV animals for threonine, serine, aspartic acid, glutamic acid, histidine, tyrosine and phenylalanine.
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PMID:Dietary fiber viscosity and amino acid digestibility, proteolytic digestive enzyme activity and digestive organ weights in growing rats. 820 41

To get a better understanding of the role of the previously reported fibrinogenolytic enzyme of Aspergillus fumigatus, we investigated the in vitro conditions of enzyme synthesis and attempted to characterize it. Modification of the nitrogen source did not influence the extracellular serine-proteinase profile, but resulted in important quantitative differences in the yields in batch cultures. The enzyme synthesis appeared to be an inducible phenomenon in A. fumigatus since it was initiated exclusively in the presence of proteins or protein hydrolysate. Free amino acids or inorganic nitrogen compounds could not promote significant enzyme production. Moreover, peptone at a concentration of 0.1% appeared to be the best inducer of enzyme synthesis. Conversely, modification of the carbon source did not affect fungal growth or enzyme synthesis. However, the production of chymotrypsin was highly sensitive to the carbohydrate level in the culture medium and, with peptone as nitrogen source, highest yields were obtained in the presence of 0.3 or 0.5% glucose. Culture filtrates of A. fumigatus CBS 113.26 grown with peptone or nitrate as nitrogen source were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Comparison of the protein patterns suggested for the proteinase a molecular mass of 33 kDa which was confirmed by chromatographic purification of the enzyme through (N alpha-CBZ)-D-phenylalanine agarose.
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PMID:Extracellular fibrinogenolytic enzyme of Aspergillus fumigatus: substrate-dependent variations in the proteinase synthesis and characterization of the enzyme. 836 26

Mouse oocyte-cumulus masses were added to 1.5 dimethyl sulphoxide (DMSO) + 20% fetal bovine serum (FBS) that had been precooled at +4 degrees C, were frozen by slow cooling to an intermediate temperature of -60 degrees C before being plunged into liquid nitrogen at -196 degrees C, subjected to a controlled thaw, expelled into 1.5 M DMSO + FBS at 4 degrees C, and then washed in medium + FBS at 37 degrees C. Of 7733 oocytes treated, 78.4% were viable (controls; no treatment: 94.2% of 2764 oocytes; cryoprotectant only: 92.2% of 2991 oocytes). The oocyte losses were not due to complete loss of all oocytes from some straws or mice, since analysis of individual straws containing oocytes from a single mouse revealed considerable inter-straw/mouse variation. Amongst surviving oocytes, no significant differences between frozen and control oocytes in spindle, chromosomal or microfilament organization were recorded. Two significant differences were observed: (i) fewer frozen-thawed oocytes had zonae resistant to chymotrypsin digestion, and (ii) spindle organization in control oocytes, but not frozen-thawed oocytes, was improved by 3 h incubation at 37 degrees C. More of the abnormal than the normal frozen-thawed and control oocytes were surrounded by zonae which were resistant to digestion by chymotrypsin.
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PMID:Cytoskeletal organization and zona sensitivity to digestion by chymotrypsin of frozen-thawed mouse oocytes. 825 47

Two 15-d nutrient balance trials were conducted using a total of 32 weanling barrows (averaging 6.8 kg, 26 d). The effect of the addition of 15 or 250 ppm Cu (as CuSO4.5H2O) to diets containing 0 or 5% added animal fat on nutrient utilization, digestive enzyme activities, and tissue mineral levels in weanling pigs was investigated. In each trial, four groups of four littermate barrows were randomly assigned to one of four treatments in a 2 x 2 factorial arrangement. The addition of 250 ppm Cu improved apparent fat digestibility and apparent nitrogen retention (P < .02). The addition of 5% fat increased apparent fat digestibility (P < .01). There were no Cu x fat interactions (P > .10) for any of the digestibility indices measured. The addition of 250 ppm of Cu stimulated small intestinal lipase (P < .01) and phospholipase A (P < .05) activities but had no effect (P > .10) on pancreatic lipase or phospholipase activities and no effect on trypsin, chymotrypsin, or amylase activities in the small intestine or the pancreas. The addition of 250 ppm Cu to the diet increased Cu (P < .001) in plasma, liver, and kidney and decreased Fe in plasma (P < .05) and liver (P < .02). The addition of 5% fat increased Fe in kidney (P < .05) and heart (P < .08). Copper x fat interactions were observed for spleen Ca (P < .01), Mg (P < .08), Na (P < .05), and K (P < .08) and spleen weight (P < .05). In additional in vitro assays, increased Cu concentrations tended to consistently stimulate purified porcine pancreatic lipase activity (linear, P < .01) but not purified porcine pancreatic phospholipase A activity (P > .10). The results from this study indicate that 250 ppm Cu stimulated intestinal lipase and phospholipase A activities, leading to an improvement of dietary fat digestibility in weanling pigs.
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PMID:Effect of dietary copper and fat on nutrient utilization, digestive enzyme activities, and tissue mineral levels in weanling pigs. 885 43

We describe a simple and effective procedure to screen for active proteases among a large number of mutants. First, the mutants are genetically tested by the protease activity produced in the periplasm of transformed bacteria which supplies the cells with a nitrogen source by hydrolyzing a protein applied to plates. Then a less sensitive activity staining and an X-ray film digestion assay are used to verify and estimate the activity of the mutants that proved to be positive in the first step. Depending essentially on the level of periplasmic protease activity, the method can detect both the activity and the stability of the expressed enzymes. We calibrated the method with transformants that produce wild-type trypsin, chymotrypsin and trypsin mutants of known activity. Using this method we found two active revertants of the inactive Asn102 trypsin mutant, by screening approximately 4.4 x 10(4) random mutants that were generated by the polymerase chain reaction on a cDNA fragment. This procedure should be useful in searching for proteases of novel specificity and/or reaction chemistry engineered by random mutagenesis, and also for in vitro evolution studies.
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PMID:A rapid and effective procedure for screening protease mutants. 905 7

An in vitro normal human epidermal keratinocytes (NHEK) model was used to study and to characterize the protease stimulated by the mustards 2-chloroethyl ethyl sulphide (CEES), 2-chloro-N-(2-chloroethyl)-N-methylethanamine hydrochloride (nitrogen mustard, HN2), and Bis-2-chloroethyl sulfide (sulfur mustard, HD). The results obtained by using a chromozym (TRY) peptide substrate protease assay showed the optimum mustard concentration and time for protease stimulation to be about 200 microM CEES, 100 microM HN2 or HD, and 16 hours. The mustard-stimulated protease was membrane-bound, and was inhibited by adding a Ca2+ chelator EGTA (2 mM), BAPTA AM (50 microM) or a serine protease inhibitor diisopropyl fluoro-phosphate DFP (1 mM), or a protein synthesis inhibitor cycloheximide (10 microM) in the extracellular medium. These results suggest that one of the mechanisms of mustard toxicity is via the stimulation of a trypsin/chymotrypsin like serine protease, which is dependent on Ca2+ and new protein synthesis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a mustard-stimulated approximately equal to 70-80 KDa protein band that was associated with protease activity which was inhibitable by EGTA, BAPTA, DFP or cycloheximide. This mustard-stimulated protein (protease) may serve as a diagnostic tool for mustard exposure as well as an assay for screening prospective antivesicant protease inhibitor drugs.
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PMID:Protease in normal human epidermal keratinocytes. 970 64

The crystal structure of the 2A proteinase from human rhinovirus serotype 2 (HRV2-2A(pro)) has been solved to 1.95 A resolution. The structure has an unusual, although chymotrypsin-related, fold comprising a unique four-stranded beta sheet as the N-terminal domain and a six-stranded beta barrel as the C-terminal domain. A tightly bound zinc ion, essential for the stability of HRV2-2A(pro), is tetrahedrally coordinated by three cysteine sulfurs and one histidine nitrogen. The active site consists of a catalytic triad formed by His18, Asp35 and Cys106. Asp35 is additionally involved in an extensive hydrogen-bonding network. Modelling studies reveal a substrate-induced fit that explains the specificity of the subsites S4, S2, S1 and S1'. The structure of HRV2-2A(pro) suggests the mechanism of the cis cleavage and its release from the polyprotein.
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PMID:The structure of the 2A proteinase from a common cold virus: a proteinase responsible for the shut-off of host-cell protein synthesis. 1052 91

We determined whether pancreatic adaptation to a high-protein diet depends on ingested protein in the intestinal lumen and whether such adaptation depends on a CCK or capsaicin-sensitive vagal afferent pathway in pancreaticobiliary-diverted (PBD) rats. Feeding a high-casein (60%) diet but not a high-amino acid diet to PBD rats increased pancreatic trypsin and chymotrypsin activities compared with those after feeding a 25% casein diet. In contrast, feeding both the high-nitrogen diets induced pancreatic hypertrophy in PBD rats. These pancreatic changes by the diets were abolished by treatment with devazepide, a CCK-A receptor antagonist. Protease zymogen mRNA abundance in the PBD rat was not increased by feeding the high-casein diet and was decreased by devazepide. Perivagal capsaicin treatment did not influence the values of any pancreatic variables in PBD rats fed the normal or high-casein diet. We concluded that luminal protein or peptides were responsible for the bile pancreatic juice-independent induction of pancreatic proteases on feeding a high-protein diet. The induction was found to be dependent on the direct action of CCK on the pancreas. Pancreatic growth induced by high-protein feeding in PBD rats may depend at least partly on absorbed amino acids.
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PMID:Luminal dietary protein, not amino acids, induces pancreatic protease via CCK in pancreaticobiliary-diverted rats. 1085 24

The synthesis of cell-associated and secreted proteins by Streptococcus gordonii FSS2, an infective endocarditis (IE) isolate, was influenced by both environmental pH and carbon source. Controlling the pH at 7.5 in stirred batch cultures showed that cell-associated and secreted protein concentrations were increased during late exponential and stationary phase by 68% and 125%, respectively, compared with similar cultures without pH control. The expression of five glycosidase and eight peptidase activities were examined using fluorogen-labelled synthetic substrates. Enzyme activities were significantly down-regulated during exponential growth, increasing during stationary phase (P<0.01) whether the culture pH was controlled at pH 7.5 or allowed to fall naturally to pH 4.4. Culture-supernatant activities were significantly increased (P<0.05) when the pH was maintained at 6.0 or 7.5, indicating modulation of enzyme activity by pH. Growth under nitrogen-limitation/glucose-excess conditions resulted in a significant repression of cell-associated glycosidase activities (P<0.01), whilst in the supernatant, activities were generally reduced. The expression of peptidase activities in the culture supernatant did not significantly change. The results suggest a possible role for catabolite repression by glucose in regulating enzyme expression. When S. gordonii FSS2 was cultured with 50% (v/v) added heat-inactivated foetal bovine serum, several cell-associated enzyme activities increased initially but were then reduced as the culture time was extended to 116 h. Culture-supernatant enzyme activities (N-acetyl-beta-D-glucosaminidase, N-acetyl-beta-D-galactosaminidase, thrombin, Hageman factor, collagenase and chymotrypsin), however, were significantly increased (P<0.01) over the same time period. The findings indicated that most of the important glycosidases synthesized by S. gordonii FSS2 were down-regulated by acid growth conditions and may also be subject to catabolite repression by glucose but conversely may be up-regulated by growth in serum. These results may have implications for streptococcal growth in an IE vegetation and in the mouth between meals or during sleep.
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PMID:Environmental regulation of glycosidase and peptidase production by Streptococcus gordonii FSS2. 1093 96

Two fermented milks containing angiotensin-I-converting-enzyme (ACE)-inhibitory peptides were produced by using selected Lactobacillus delbrueckii subsp. bulgaricus SS1 and L. lactis subsp. cremoris FT4. The pH 4.6-soluble nitrogen fraction of the two fermented milks was fractionated by reversed-phase fast-protein liquid chromatography. The fractions which showed the highest ACE-inhibitory indexes were further purified, and the related peptides were sequenced by tandem fast atom bombardment-mass spectrometry. The most inhibitory fractions of the milk fermented by L. delbrueckii subsp. bulgaricus SS1 contained the sequences of beta-casein (beta-CN) fragment 6-14 (f6-14), f7-14, f73-82, f74-82, and f75-82. Those from the milk fermented by L. lactis subsp. cremoris FT4 contained the sequences of beta-CN f7-14, f47-52, and f169-175 and kappa-CN f155-160 and f152-160. Most of these sequences had features in common with other ACE-inhibitory peptides reported in the literature. In particular, the beta-CN f47-52 sequence had high homology with that of angiotensin-II. Some of these peptides were chemically synthesized. The 50% inhibitory concentrations (IC(50)s) of the crude purified fractions containing the peptide mixture were very low (8.0 to 11.2 mg/liter). When the synthesized peptides were used individually, the ACE-inhibitory activity was confirmed but the IC(50)s increased considerably. A strengthened inhibitory effect of the peptide mixtures with respect to the activity of individual peptides was presumed. Once generated, the inhibitory peptides were resistant to further proteolysis either during dairy processing or by trypsin and chymotrypsin.
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PMID:Production of angiotensin-I-converting-enzyme-inhibitory peptides in fermented milks started by Lactobacillus delbrueckii subsp. bulgaricus SS1 and Lactococcus lactis subsp. cremoris FT4. 1096 6


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