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 ornithine decarboxylase-inducing factor (ODC factor) was purified about 1,000-fold in 42% yield from the ascites fluids of an Ehrlich ascites tumor by a combination of centrifugation and concanavalin A (ConA) treatment. A single ip injection of 0.5 micrograms of the purified factor per mouse resulted in half-maximum induction of liver ODC. The factor was found to be a trypsin- and chymotrypsin-resistant, acidic glycoprotein (pI about 4.43) with a minimum molecular weight of about 70 kilodaltons, containing a disulfide bond(s) in its functional domain. It did not react with ConA. This factor induced retrodifferentiation of liver function, causing a marked increase of prototype M2 isozyme of pyruvate kinase. It reduced liver catalase activity, and also modified thyroid hormone metabolism, reducing the serum levels of T4 and T3. These results suggest that the ODC factor is multifunctional and induces many of the changes observed in a tumor-bearing host.
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PMID:Purification of ornithine decarboxylase-inducing factor from cell-free ascites fluid of Ehrlich ascites tumor and its characteristics. 170 56

Benzoyl- and isopentenoyl phosphoric triamides (BPA and IPA) strongly inhibited urease activities from jack bean, soybean, watermelon seed, Proteus mirabilis, P. rettgeri, P. vulgaris, Mycobacterium smegmatis, and Ureaplasma urealyticum. Their I50 values (the final concentration causing 50% inhibition), independent of enzyme source, were 2-21 nM, which are about 1,000-fold lower than that of caprylohydroxamic acid, one of the most potent urease inhibitors. ATP-urea amidolyase activity was inhibited 50% by BPA at a higher concentration of 0.28 mM, but was not affected by IPA even at 1.3 mM. Thirteen kinds of hydrolases (trypsin, chymotrypsin, thermolysin, leucine aminopeptidase, papain, lipase, alpha-amylase, glucuronidase, asparaginase, arylsulfatase, alkaline phosphatase, acid phosphatase, and true cholinesterase), two oxidoreductases (catalase and alcohol dehydrogenase), three transferases (glutamic-oxaloacetic aminotransferase, gamma-glutamyl transpeptidase, and arylsulfotransferase) and two kinases (pyruvate kinase and creatine kinase) were not affected at all even at 1 mM BPA and IPA. Exceptionally, pseudo-cholinesterase from human serum was inhibited by BPA and IPA, whose I50 values were 70 nM and 10 muM, respectively, using acetylthiocholine as a substrate. These values increased to 0.55 muM and 54 muM, respectively, when acetylcholine was used as a substrate. These results show that N-acylphosphoric triamides potently and specifically inhibit urease activity at concentrations of nM order.
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PMID:Specific inhibition of urease by N-acylphosphoric triamides. 384 42

1. The possibility of stabilizing water-soluble enzymes against the inactivation action of organic solvents by means of surfactants has been studied. Several enzymes (alpha-chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), pyrophosphatase (EC 3.6.1.1), peroxidase (EC 1.11.1.7), lactate dehydrogenase (EC 1.1.1.27) and pyruvate kinase (EC 2.7.1.40)) were used to demonstrate that enzymes can be entrapped into reversed micelles formed by surfactants (Aerosol OT, cetyltrimethylammonium bromide, Brij 56) in an organic solvent (benzene, chloroform, octane, cyclohexane). The enzymes solubilized in this way retain their catalytic activity and substrate specificity. 2. A kinetic theory has been put forward that describes enzymatic reactions occurring in a micelle-solvent pseudobiphasic system. In terms of this theory, an explanation is given for the experimental dependence of the Michaelis-Menten equation parameters on the concentrations of the components of a medium (water, organic solvent, surfactant) and also on the combination of the signs of charges in the substrate molecule and on interphase (++, +-, --). 3. The results obtained by us may prove important for applications of enzymes in organic synthesis and for studying the state and role of water in the structure of biomembranes and active centres of enzymes.
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PMID:The principles of enzyme stabilization. VI. Catalysis by water-soluble enzymes entrapped into reversed micelles of surfactants in organic solvents. 721 47

A fluorescent study of some structural and functional properties of conjugates of a number of proteins (bovine serum albumin, pyruvate kinase, alpha-chymotrypsin, and the two toxic proteins of plant origin--ricin and viscumin) with polyalkylene oxides (polyethylene glycol and pluronic) has been carried out. Analysis of the intrinsic protein fluorescence showed that the structure and stability of various protein conjugates to denaturing agents change only slightly: the conformational mobility of tryptophan residues accessible to the solvent decreases, whereas that of tryptophan residues localized in the protein regions of low polarity remains unchanged. Besides, the conjugates display a higher thermal stability in comparison with their native proteins. The fluorescence of 1-anilinonaphthalene-8-sulfonic acid and water insoluble 2',3',4',5'-tetrabenzoylriboflavin bound to the native and modified proteins indicated that modification of the proteins with polyalkylene oxides decreased the polarity and increased the viscosity of the microenvironment. Hence, this modification makes it possible to change some functional characteristics of the protein without causing any significant changes in its structure.
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PMID:[Structure-functional properties of conjugates of proteins with polyalkylene oxides: study by a fluorescence method]. 829 53

Various proteins/enzymes obtained commercially were tested for the presence of endogenously nitrated tyrosine by Western blot analysis omitting reducing agent in the step of SDS-PAGE. Histones II-S and VIII-S, IgG, cAMP-dependent protein kinase (PKA), phosphorylase b, and phosphorylase kinase exhibited strong immunoreactive bands. Histone VI-S, glycogen synthase, lactate dehydrogenase, actin, thyroglobulin, and macroglobulin exhibited moderate immunoreactivity. Histone III-S, casein, acetyl cholinesterase, DNase I, and lipase had only traceable immunoreactivity. Whereas histone VII-S, pyruvate kinase, trypsin, pepsin, chymotrypsin, protease IV, and protease XIII, and glutathione S-transferase lacked immunoreactivity. A variation of immunoreactivity between hypertensive and normaltensive rat hearts was found in the histone-agarose fractions of crude extracts. Additionally, nitrotyrosine immunoreactivity was observed in non-mammalian organisms including Eschericia coli, Saccharomyces cerevisiae and Triticum vulgaris. Upon the treatment of 15 microM peroxynitrite (PN), strong oxidant derived from nitric oxide (NO), the apparent Km of PKA for cAMP increased from approximately 10(-8) to 10(-6) M. The results imply that the varied nitration of tyrosine residues in proteins/enzymes may occur as a post-translational modification in vivo, and such discriminative nitration may be vital in PN/NO-regulated signal transduction cascade.
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PMID:Protein nitration. 1119 83

Automated analyses were used to determine the effect of retinol on the activity of the following proteolytic enzymes: ficin (EC 3.4.4.12), bromelain (EC 3.4.4. 24), trypsin (EC 3.4.4.4.), chymotrypsin A (EC 3.4.4.5), papain (EC 3.4.4.10), clostridiopeptidase A (EC 3.4.4.19), pepsin (EC 3.4.4.1), cathepsin D (EC 3.4.4. 23) from rat-liver and rat-kidney lysosomes and the nonspecific proteolytic enzyme, pronase. Of these proteolytic enzymes only ficin, bromelain, and rat-kidney lysosomal cathepsin D were inhibited significantly by 1x10(-4) M retinol.Some nonproteolytic enzymes not inhibited by retinol were acid phosphatase (EC 3.1.3.2), beta-acetylglucosaminidase (EC 3.2.1.30), arylsulfatase (EC 3.1.6.1), and pyruvate kinase (EC 2.7.1.40). The inhibition of cathepsin D varied with the substrate used, being greater with hemoglobin than with ovalbumin or bovine serum albumin. Carotene and retinol inhibited ficin and cathepsin D to similar extents. Retinol inhibition of ficin was partially reversible. These studies of proteolytic enzyme inhibition by retinol serve as a simple model for studying retinol-protein interactions in vitro.
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PMID:Retinol inhibition of some proteolytic enzymes. 1780 59