Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Taste receptors for L-alanine in the channel catfish Ictalurus punctatus have been partially characterized. The binding activity, which is localized to a sedimentable fraction (Fraction P2), was assayed with L-[3H]alanine as the ligand. 2. Addition of HgCl2 or p-mercuribenzoate to the assay at 0.1-1 mM markedly inhibited binding. The effect was not reversible and was unaffected by increased L-alanine in the binding assay. 3. The sulfhydryl reagents iodoacetate, 5,5'-dithiobis(2-nitrobenzoic acid), arsenite, and N-ethylmaleimide did not show appreciable inhibition of binding. The results suggest that the inhibitory effect of mercurials is not on specific sulfhydryl groups at alanine-binding sites. 4. Treatment of Fraction P2 with phospholipase C decreased binding activity and treatment with trypsin led to increased binding activity.
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PMID:Biochemical studies of taste sensation--VIII. Partial characterization of alanine-binding taste receptor sites of catfish Ictalurus punctatus using mercurials, sulfhydryl reagents, trypsin and phospholipase C. 23 90

Extracts of Fusarium roseum (ATCC 12822) contain an enzyme which hydrolyzes the ornithine ester bonds of fusarinine C, a cyclic trihydroxamic acid produced by this organism. The methyl ester of Ndelta-dinitrophenyl-L-ornithine is also a substrate for the enzyme, and an assay was devised using this substrate. The enzyme exhibits a sharp maximum of activity at pH 7.5 and is extremely temperature sensitive. It is strongly inhibited by HgCl2 and p-chloromercuribenzoate, and it is competitively inhibited by Ndelta-dinitrophenyl-D-ornithine methyl ester (Ki = 0.3mM). Methyl esters of glycine, L-alanine, dinitrophenyl-L-alanine, dinitrophenyl-beta-alanine, and Ndelta-dinitrophenyl-Nalpha-acetyl-L-ornithine are not substrates, although Nepsilon-dinitrophenyl-L-lysine methyl ester is as effective as the ornithine derivative. Nonspecific lipases do not hydrolyze ornithine esters, nor does trypsin. The three ester bonds of fusarinine C are progressively hydrolyzed by the enzyme to eventually yield the monomer, fusarinine. The ferric chelate of fusarinine C is not hydrolyzed. An enzyme from Penicillium sp. was isolated with identical properties toward Nbeta-dinitro-phenyl-L-ornithine methyl ester as substrate. It also hydrolyzes N,N',N"-triacetylfusarinine C, a cyclic trihydroxamate containing Nalpha-acetylornithine ester bonds, which is produced by this organism. This substrate is hydrolyzed to Nalpha-acetylfusarine. In contrast to the Fusarium enzyme, this enzyme is fully active toward the ferric trihydroxamate chelate. However, replacement of iron by aluminum leads to a completely inactive substrate. Production of the enzyme is severely suppressed by iron in the growth medium. It is proposed that these specific ornithylesterases provide a mechanism of cellular iron release by hydrolysis of the ferric ionophores, and that an iron-exchange step occurs prior to, and is a prerequisite for, hydrolysis of the ester bonds.
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PMID:Fungal ornithine esterases: relationship to iron transport. 94 72

A marked increase in water permeability can be induced in Xenopus oocytes by injection of mRNA from tissues that express water channels, suggesting that the water channel is a protein. In view of this and previous reports which showed that proteinases may interfere with mercurial inhibition of water transport in red blood cells (RBC), we examined the influence of trypsin, chymotrypsin, papain, pronase, subtilisin and thermolysin on water permeability as well as on ATPase activity, H(+)-pump, passive H+ conductance, and Na+/H+ exchange in apical brush-border vesicles (BBMV) and endosomal (EV) vesicles from rat renal cortex. H+ transport was measured by Acridine orange fluorescence quenching and water transport by stopped-flow light scattering. As measured by potential-driven H+ accumulation in BBMV and EV, proteinase treatment had little effect on vesicle integrity. In BBMV, ecto-ATPase activity was inhibited by 15-30%, Na+/H+ exchange by 20-55%, and H+ conductance was unchanged. Osmotic water permeability (Pf) was 570 microns/s and was inhibited 85-90% by 0.6 mM HgCl2; proteinase treatment did not affect Pf or the HgCl2 inhibition. In EV, NEM-sensitive H+ accumulation and ATPase activity were inhibited by greater than 95%. Pf (140 microns/s) and HgCl2 inhibition (75-85%) were not influenced by proteinase treatment. SDS-PAGE showed selective digestion of multiple polypeptides by proteinases. These results confirm the presence of water channels in BBMV and EV and demonstrate selective inhibition of ATPase function and Na+/H+ exchange by proteinase digestion. The lack of effect of proteinases on water transport by mercurials. We conclude that the water channel may be a small integral membrane protein which, unlike the H(+)-ATPase and Na+/H+ exchanger, has no functionally important membrane domains that are sensitive to proteolysis.
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PMID:Proteinases inhibit H(+)-ATPase and Na+/H+ exchange but not water transport in apical and endosomal membranes from rat proximal tubule. 130 58

The oral spirochaete Treponema denticola ATCC 33520 was grown at a mean generation time of 10 h in anaerobic continuous culture in a serum- and carbohydrate-free medium at pH 7.0. The extracellular proteolytic activities of this spirochaete were then investigated by incubating washed cells with 68 2-naphthylamide derivatives of the Extended API System. Chymotrypsin-like, trypsin-like, elastase-like and iminopeptidase activities were demonstrated. The phenylalanine peptidase or chymotrypsin-like activity of T. denticola ATCC 33520, estimated with N-succinyl-L-phenylalanyl-L-leucyl-L-phenylalanine-thiobenzyl ester (SPLP) had a pH optimum at pH 8.5, a specific activity of 36.6 nmol min-1 (mg dry wt)-1 and was inhibited only slightly by HgCl2. The trypsin-like activity, estimated with benzoyl-DL-arginine-7-amido-4-methylcoumarin (BAMC), had a pH optimum at pH9, and a specific activity of 0.3 nmol min-1 (mg dry wt)-1; inhibition by HgCl2 indicated the involvement of active thiol groups. The activity should preferably be termed arginine peptidase activity, according to the carboxy-terminal amino acid of the test substrate. The extracellular proline peptidase activity, estimated with L-proline-7-amido-4-methylcoumarin. HBr (PRAMC), had an activity of 1.5 nmol min-1 (mg dry wt)-1, an optimum at pH 8.5 and the properties of a thiol protease. The main cell-bound and extracellular active peptidase activities of fast-growing cells of T. denticola ATCC 33520 are phenylalanine peptidase, proline peptidase, arginine peptidase and an oligopeptide-dependent alanine peptidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cell-bound peptidase activities of Treponema denticola ATCC 33520 in continuous culture. 140 87

To study the mechanisms of activation of human neutrophil gelatinase, the enzyme has been purified using a combination of chromatography on a DEAE-Sephacel and a gelatin-peptide-Sepharose column. On reducing SDS-polyacrylamide-gel electrophoresis the purified gelatinase ran as a single band of about 94,000 Da, and had a specific activity of 5624.4 units/mg of enzyme protein. When latent gelatinase was treated with trypsin, cathepsin G, neutrophil elastase, HgCl2 or urea, its activity was enhanced and the enzyme was processed and converted into species of the lower molecular mass. Upon activation, the protein band of 94,000 Da of reduced latent gelatinase underwent a decrease of about 6,000-12,000 Da. Formation of the species of lower molecular mass during urea activation could be blocked by the addition of EDTA.
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PMID:The activation of human neutrophil gelatinase. 196 83

Latent collagenase has been isolated in pure form from the rheumatoid synovial fluid. The final preparation, activated by trypsin, yielded a collagenase of specific activity 2,227 units/mg. Electrophoresis in sodium dodecyl sulfate polyacrylamide gels revealed a protein doublet of 54 and 50 kDa. Trypsin or HgCl2 activation resulted in disappearance of the doublet and emergence of a new doublet of 47 and 43 kDa. The latent collagenase could also be activated by leucocyte cathepsin G or plasmin. Neither the latent nor the active collagenase from synovial fluid showed any cross-reactivity with the antibodies against leucocyte collagenase. The trypsin activated collagenase degraded collagen type I, II, III giving typical cleavage products but did not degrade type IV and V collagen.
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PMID:Some properties of latent collagenase from human synovial fluid. 196 84

The neutral protease tryptase has been isolated from a human mast cell line, HMC-1. The HMC-1 line was established from the peripheral blood of a patient with mast cell leukemia and maintained as continuously proliferating clones in vitro and as solid mast cell tumors in nude mice. HMC-1-derived tryptase was purified by sequential chromatography on Dowex 1, DEAE 5 PW, and heparin-agarose. Purified tryptase has an apparent molecular weight of 150,000, as determined by molecular sieve HPLC, but migrates as a doublet of bands of 32/35,000 on SDS-PAGE gels. Maximal enzymatic activity was observed at pH 8.5. Cleavage of tosyl-L-arginine methyl ester by purified tryptase was inhibited by dansyl-L-glutamyl-glycyl-L-arginine chloromethyl ketone 2 HCl, HgCl2, tosyl-L-lysine chloromethyl ketone, leupeptin, and PMSF but not by benzamidine, aprotinin, tosyl-L-phenyl-alanine chloromethyl ketone, soybean trypsin inhibitor, human plasma, ovomucoid inhibitor, or lima bean trypsin inhibitor. Microsequencing of purified tryptase yielded an amino terminal sequence that was identical to that previously reported for human pituitary-derived tryptase.
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PMID:Purification of tryptase from a human mast cell line. 211 May 91

Experiments were performed to demonstrate the involvement of electron transport system in fatty acid elongation in rat brain microsomes. Mercuric chloride and p-chloromercuriphenylsulfonate, inhibitors on NADH-cytochrome b5 reductase, at 32 microM inhibited NADH-supported palmitoyl-CoA elongation to 30 and 60% of control activity, respectively, whereas NADPH-supported palmitoyl-CoA elongation was unaffected by these mercurials. An antibody to rat liver NADH-cytochrome b5 reductase inhibited brain microsomal NADH-cytochrome b5 reductase activity and NADH-dependent palmitoyl-CoA elongation. Treatment of brain microsomes with trypsin diminished the cytochrome b5 content; NADH- and NADPH-cytochrome c reductase activities were significantly decreased, but the decrease in NADH-cytochrome b5 reductase activity was relatively small. Whereas essentially no incorporation of malonyl-CoA into palmitoyl-CoA was observed with trypsin-treated microsomes, addition of detergent-solubilized cytochrome b5 resulted in a recovery of fatty acid elongation. These results indicate the presence of an electron transport system, NADH-NADH-cytochrome b5 reductase-cytochrome b5-fatty acid elongation, in brain microsomes.
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PMID:Palmitoyl-CoA elongation in brain microsomes: dependence on cytochrome b5 and NADH-cytochrome b5 reductase. 299 84

Female SJL and Balb/c mice were given subcutaneous injections of 1.6 mg HgCl2/kg body weight every third day for 2, 4, 8, or 12 weeks. Indirect immunofluorescence using HEp-2 cells as substrate showed that SJL mice developed antinuclear antibodies (ANA) with a predominantly nucleolar and a weaker, homogeneous nuclear pattern after 4 weeks treatment. The nucleolar antigen was sensitive to treatment with trypsin and RNAse, but the antibody was not absorbed by calf liver RNA. The antigen responsible for the homogeneous nuclear pattern was sensitive to treatment with trypsin, DNAse, and acid solution, but reconstitution with histones on acid treated substrate did not restore the fluorescence. The corresponding antibody was not absorbed by double-stranded or single-stranded DNA, and the Crithidia luciliae assay was negative. This suggests that the antigen responsible for the homogeneous ANA pattern is a non-histone chromatin protein. No autoantibodies were found in Balb/c mice. Electron dense immune deposits containing IgG and C3 in a mesangial-vascular pattern developed after 4 weeks mercury treatment in SJL and Balb/c mice. Acid eluate from kidneys of SJL mice with immune deposits contained tissue-bound ANA with a strictly anti-nucleolar pattern, showing that such antibodies make up part of the renal immune deposits. No autoantibodies were found in the eluate from Balb/c mice. The findings demonstrate that mercury induces a polyclonal autoantibody response in SJL mice, and suggests a restricted antibody response with unknown specificity in Balb/c mice, in both cases leading to immune complex deposits in the kidneys.
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PMID:Mercury induced antinuclear antibodies in mice: characterization and correlation with renal immune complex deposits. 328 Jan 86

Previous studies have demonstrated the presence of two type III hexokinase isozymes in pig mature erythrocytes. The prevalence of a specific isozyme species is an age-dependent phenomenon. The mature erythrocyte of young adult pigs (less than 6 mo old) possess an isozyme that has an apparent Km for glucose that is lower than in adult pigs. The data in this report suggest several basic differences between the two isozymes. D-Mannoheptulose, a structural analogue of glucose, was observed to differentially inhibit the isozymes. The young adult isozyme tended to be heat sensitive when compared with adult isozymes. Carboxypeptidase B and trypsin inhibited the activity of both isozymes, but the young adult isozyme was most dramatically affected by carboxypeptidase B. When the two isozymes were incubated in the presence of two sulfhydryl group inhibitors, HgCl2 and 5,5'-dithiobis [2-nitrobenzoic acid] (DTNB), the young adult isozyme exhibited the greater inhibition in the presence of DTNB. The data suggest that the young adult isozyme exhibited pronounced differences in activity when incubated in the presence of DTNB and carboxypeptidase B. These two agents may be used as probes to further characterize the properties of the two isozymes.
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PMID:Properties of pig mature erythrocyte hexokinase. 407 95


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