Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: C01B12 .4
 471,332 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The reactivities of phenylglyoxal (PGO), glyoxal (GO), and/or methylglyoxal (MGO) with several proteins, including ribonuclease A [EC 3.1.4.22] and its derivatives, alpha-chymotrypsin [EC 3.4.21.1], trypsin [EC 3.4.21.4], lysozyme [EC 3.2.1.17], pepsin [EC 3.4.23.1], rennin [EC 3.4.23.4], thermolysin, and insulin and its B chain, have been examined. From analyses of the reaction products, PGO was shown to be the most specific for arginine residues. GO and MGO also reacted rapidly with arginine residues, but they also reacted with lysine residues to a significant extent. A side reaction with N-terminal alpha-amino groups was observed with each of these reagents. 2. Two arginine residues out of four in ribonuclease A, two out of three in alpha-chymotrypsin, one out of two in trypsin, one out of two in pepsin, and one out of five in rennin appeared to react with PGO fairly rapidly, indicating a difference in the relative accessibility of these residues by the reagent. Extensive modification of the arginine residues by PGO occurred with RCM-derivatives of ribonuclease A and insulin B chain. The N-terminal isoleucine residues of alpha-chymotrypsin and trypsin appeared to be unreactive with PGO because of salt bridge formation with an aspartyl residue. The activity of alpha-chymotrypsin toward N-benzoyl-L-tyrosine ethyl ester and the lytic activity of lysozyme were lost rapidly on treatment with PGO, as in the case of ribonuclease A. Pepsin and rennin were only partially inactivated by reaction with PGO.
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PMID:Further studies on the reactions of phenylglyoxal and related reagents with proteins. 32 41

Isolated membrane fractions of Escherichia coli K-12 yielded complex immunoprecipitate patterns when Triton X-100 and sodium dodecyl sulfate extracts were examined by crossed immunoelectrophoresis with antienvelope immunoglobulins. Twelve of the 46 antigens in the immunoprecipitate patterns of inner (plasma) membranes were identified by zymograms and/or by the use of specific antisera. The following enzyme activities were detected in immunoprecipitates: 6-phosphogluconate dehydrogenase (EC 1.1.1.43); adenosine triphosphatase (EC 3.6.1.3); glutamate dehydrogenase (EC 1.4.1.4), two separate components; malate dehydrogenase (EC 1.1.1.37); dihydroorotate dehydrogenase (EC 1.3.3.1); succinate dehydrogenase (EC 1.3.99.1); lactate dehydrogeanse (EC 1.1.1.27); reduced nicotinamide adenine dinucleotide dehydrogenase (EC 1.6.99.3); protease (EC 3.4.21.1); and glycerol 3-phosphate dehydrogenase (EC 1.1.99.5). The corresponding immunoprecipitate pattern for isolated outer membranes consisted of at least 25 discrete antigens and differed strikingly from that obtained with inner membranes. Two major immunogens were identified as lipopolysaccharide and Braun lipoprotein. A protease-active immunoprecipitate was also detected in this fraction, but attempts to identify the Rosenbusch matrix protein in the crossed immunoelectrophoretic profile were unsuccessful.
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PMID:Immunochemical analysis of inner and outer membranes of Escherichia coli by crossed immunoelectrophoresis. 33 83

Three natural proteinase isoinhibitors with low isoelectric points BUSI I A (pI = 3.9), BUSI I B1 (pI = 3.4 and BUSI I B2 (pI = 3.7) were isolated from bull seminal plasma by gel filtration on Sephadex G-50 and ion exchange chromatography on DEAE-Sephadex and SE-Sephadex. Isoinhibitors Bl and B2 have identical amino acid composition. Isoinhibitor A contains six amino acid residues less than isoinhibitors B1 and B2. Since sugars have been detected in the isoinhibitors, heterogeneity may also be due to the sugar component. The isoinhibitors show the same inhibitory properties; all of them inhibit acrosin, trypsin and chymotrypsin. Glandular kallikrein is also inhibited, but to a very low extent only. The molecular weight (Mr approximately 8 900) was determined by gel filtration.
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PMID:Isolation of acidic acrosin isoinhibitors (BUSI I A, BUSI IB1 and BUSI I B2) from bull seminal plasma. 39 5

Human granulocyte elastase (EC 3.4.21.11) differs from hog pancreatic elastase in its specificity for synthetic substrates. Although hydrolyzing peptide bonds adjacent to the carboxyl group of alanine, the granulocyte enzyme prefers valine at the cleaved bond, in contrast to the pancreatic enzyme which prefers alanine. Peptide bonds involving the carboxyl group of isoleucine can be hydrolyzed by the granulocyte enzyme but are not hydrolyzed to any significant extent extent by pancreatic elastase. This difference in specificty could explain the lower sensitivity of the granulocyte enzyme to inhibitors containing alanine analogs, such as the peptide chloromethyl ketones and elastatinal. The human granulocyte chymotrypsin-like enzyme differs from pancreatic chymotrypsin by being able to cleave substrates containing leucine in addition to those containing the aromatic amino acids.
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PMID:Sbustrate specificity of the elastase and the chymotrypsin-like enzyme of the human granulocyte. 40 49

Enterotoxin B produced by Staphylococus aureus 243 in brain heart infusion broth was concentrated by dialysis against 40% polyethylene glycol (20 M), partially purified on a Sephadex G-100 column and heated at 110 degrees C in thermal death time cans. Various heating menstrua included 0.04 M Veronal buffer (pH 7.4), beef broth, and fractions of beef broth obtained by ultrafiltration or precipitation with ammonium sulfate. The toxin was assayed serologically using the microslide gel double-diffusion method. The time requiring for 90% inactivation at 110 degrees C (D110 value) obtained in buffer and in beef broth was 18 and 60 min, respectively. When the concentration of beef broth was increased fivefold, the D110 increased to 78 min. The apparent protective effect or protein was further investigated using beef broth protein obtained by precipitation with (NH4)2SO4. The D110 values were 51 and 70 min when the protein concentration in the heating menstruum was 3.8 and 7.7 mg/ml, respectively. However, when the beef broth protein was dialyzed against buffer before use as a heating menstrum, the D110 was only 39 or 41 min at comparable protein concentrations. Results indicated a dialyzable factor, whose protective effect was partially destroyed by trypsin and chymotrypsin but did not by disodium ethylenediaminetetraacetate, was involved in the protection of enterotoxin B during heating.
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PMID:Effect of beef broth protein on the thermal inactivation of staphylococcal enterotoxin B1. 40 60

The binding of the fluorescence probe 1-anilinonaphthalene-8-sulfonate (Ans) to alpha-chymotrypsin (alpha-CHT) at pH 3.6 is accompanied by a dramatic enhancement of Ans fluorescence and a shift of the emission maximum to shorter wavelengths. Our study reveals that one Ans molecule binds to alpha-CHT at a site different from either the active site of alpha-CHT or the 2-p-toluidinylnapthalene-6-sulfonate binding site. the binding constant of Ans is about the same (10(4) M-1) at pH 3.6 and 6.4. Nanosecond fluorescence depolarization data indicate that Ans is rigidly bound to alpha-CHT. The fluorescence enhancement due to binding of Ans to alpha-CHT at low pH could be due to binding either to a hydrophobic site or to a site where local dipoles do not relax during the excited-state lifetime of Ans. As the pH is increased, fluorescence intensity of the Ans-alpha-CHT complex decreases appreciably; and the emission maximum shifts to longer wavelengths. The fluorescence decay curves exhibit a corresponding sensitivity to pH. The pH effect on the fluorescence of Ans-alpha-CHT can be interpreted in terms of a pH-dependent equilibrium between alpha-CHT conformers differing in the degree of mobility of polar residues and water molecules at the Ans binding site or structural changes in the Ans binding site.
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PMID:Interaction of alpha-chymotrypsin with the fluorescent probe 1-anilinonaphthalene-8-sulfonate in solution. 42 15

The denaturing action of guanidine . HCl on modified alpha-chymotrypsin (EC 3.4.21.1) preparations has been studied. The consecutive treatment of alpha-chymotrypsin with N-acetyl-homocysteine thiolactone, 5,5'-dithio-bis-(2-nitrobenzoic acid) and dithiols of HS-(CH2)n-SH type, with n ranging from 4 to 10, leads to enzyme stabilization as a result of protein modification. A greater stabilization effect can be achieved by enriching the protein molecule with groups reactive towards dithiols, after first modifying carboxygroups. In this case dithiol with n=5 forms an intramolecular cross-linkage. If an equimolecular mixture of different dithiols is used for enzyme modification, the enzyme gradually 'selects' 1,5-dithiol for the formation of an intramolecular cross-linkage instead of the initial one-point modification. The use of potentially reversible cross-linkages may be generally employed for the preparation of stabilized water-soluble enzymes via the mechanism of selfstabilization.
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PMID:Principles of enzyme stabilization. V. The possibility of enzyme selfstabilization under the action of potentially reversible intramolecular cross-linkages of different length. 44 35

p-Antimonybenzenesulfonyl fluoride and p-mercurybenzenesulfonyl fluoride irreversibly inhibit chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), and chromosomal protease, and these inhibitors appear to be as active as phenylmethanesulfonyl fluoride. The pretreatment of the proteases interferes with the phosphorylation of the active-site serine by diisopropylfluorophosphate suggesting that the organometallic inhibitors may also interact with the active site serine. The organometallic inhibitors may be used for localization of proteases in different parts of the cell by electron microscopy and p-mercurybenzenesulfonyl fluoride could also be used for isolation of proteases by sulfhydryl affinity chromatography.
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PMID:Synthesis of active site-directed organometallic irreversible protease inhibitors. 44 36

1. Sonication of bovine liver microsomes completely solubilized the membrane-bound lysophospholipase II (EC 3.1.1.5). Co-chromatography with purified 125I-labelled lysophospholipase indicated that the enzyme was solubilized from microsomes in a lipid-free state. 2. In the presence of residual microsomal membranes, the solubilized lysophospholipase could only be partly degraded by trypsin (EC 3.4.21.4). Therefore, trypsin could not be used to study the transmembrane disposition of lysophospholipase in intact microsomes. 3. Chymotrypsin (EC 3.4.21.1) destroyed the solubilized lysophospholipase activity, even in the presence of residual microsomal membranes. 4. Lysophospholipase in intact microsomal vesicles was resistant to chymotrypsin digestion. 5. When microsomal vesicles were made leaky with lysophosphatidylcholine, chymotrypsin destroyed more than 95% of the lysophospholipase activity. 6. It is concluded from these experiments that at least the active center of lysophospholipase is located at the luminal side of the bovine liver microsomal membrane.
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PMID:Studies on the transverse localization of lysophospholipase in bovine liver microsomes using proteolytic enzymes. 45 32

1. The food intake, pancreas weight and trypsin (EC 3.4.21.4) and alpha-chymotrypsin (EC 3.4.21.1) activities in the pancreas were measured in rats during pregnancy and lactation and after the young were weaned. 2. All the quantities measured increased significantly during lactation and had returned to their original values by 4 weeks after weaning. Food intake and pancreas weight were highest after the second week of lactation. Total trypsin and alpha-chymotrypsin activity, and the activity per g tissue, fell during pregnancy and rose during lactation, reaching a maximum 1 week after weaning. 3. From these and other results it is suggested that the hypertrophy and hypersecretion of pregnancy and lactation are initiated by changes insulin secretion and mediated by the trophic effects of gut hormones, and that differences in the nature and timing of the response may be controlled by nutrient availability.
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PMID:The effects of pregnancy and lactation on the activities of trypsin and alpha-chymotrypsin in the rat pancreas. 46 45


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