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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The esterase action of thrombin and trypsin on N-arylsulfonyl-valyl-arginine methyl esters was studied. The values of Km and kcat under steady-state conditions at pH 8,5 were determined. It was shown that the nature of the arylsulfonyl group does not affect the kinetic parameters of the reactions under study. The Michaelis constants of the thrombin-catalyzed reactions appeared to be one order of magnitude lower than the Km values of the corresponding TAME analogs.
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PMID:[Comparative study of hydrolysis of methyl esters of N-arylsulfonyl-valyl-arginine by thrombin and trypsin]. 3 47

The Vicia angustifolia proteinase inhibitor was incubated with p-toluenesulfonyl-L-phenylalanine chloromethyl ketone-trypsin (EC 3.4.21.4) and a main product was isolated. The purified product was different to the first trypsin-modified V. angustifolia inhibitor. The C-terminal residues of the new derivative were arginine, which was also the C-terminal of the cleaved antitryptic site; lysine was a newly exposed C-terminal. These results suggest that the new derivative lacks the C-terminal portion of the native inhibitor, which has asparagine at its C-terminus. The liberated C-terminal peptide had the following amino acid sequence: H-Glu-Glu-Val-Ile-Lys-Asn-OH. The derivative lacking the C-terminal hexapeptide still possesses inhibitory activities against trypsin and alpha-chymotrypsin (EC 3.4.21.1), however, its antichymotryptic activity was inactivated by incubation with chymotrypsin at pH 8.0.
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PMID:Isolation and activities of the trypsin-modified Vicia angustifolia proteinase inhibitor lacking carboxyl-terminal hexapeptide. 3 67

The steady-state kinetics of plasmin- (EC 3.4.21.7) and trypsin-catalysed (EC 3.4.21.4) hydrolysis of Bz-L-Phe-Val-Arg-pNA, Bz-D-Phe-Val-Arg-pNA, L-Phe-Val-Arg-pNA, D-Phe-Val-Arg-pNA and D-Val-Leu-Lys-pNA were investigated in the pH range 6-9. The pH dependences of the kinetic parameters correspond with the effects of catalytically essential ionizations in the enzymes, except for reactions with L- and D-Phe-Val-Arg-pNA, in which protonation of the NH2-terminal alpha-amino groups (pK = 7.0) shows some inhibitory effect. The reactions of plasmin and trypsin with p-nitroanilides show kc values similar to those normally found with specific ester substrates, indicating that the deacylation steps of the reactions are rate determining.
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PMID:Steady-state kinetics of plasmin- and trypsin-catalysed hydrolysis of a number of tripeptide-p-nitroanilides. 3 47

Phenylthiazolones (PTAs) of arginine and its homologs and analogs, homoarginine, norarginine (alpha-amino-gamma-guanidinobutyric acid), canavanine, and gamma-hydroxyarginine, were prepared. A steady-state kinetic analysis of the trypsin [EC 3.4.21.4]-catalyzed hydrolysis reactions was carried out and the kinetic parameters for these internal thioesters were compared with those for normal linear ester substrates. PTA-gamma-hydroxyarginine was so labile that hydrolysis by the enzyme could not be followed. PTA-arginine has a specificity constant (Kcat/Km) comparable to that for the Nalpha-unblocked arginine ester substrate, though the value is about 0.1% of that for a specific ester substrate, Nalpha-tosylarginine methyl ester. PTA derivatives of canavanine and homoarginine were hydrolyzed with Kcat/Km walues of the same order of magnitude as that for PTA-arginine. However, PTA-noraginine was much less susceptible to tryptic hydrolysis that PTA-homoarginine, while the linear esters of norarginine are known to be more susceptible than those of homoarginine.
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PMID:Kinetics of hydrolysis of phenylthiazolones of arginine, homoarginine, norarginine, and canaavanine by trypsin. 3 64

A continuous flow method has been developed for the automatic determination of enterokinase in rat small intesstine mucosa and/or luminal content. Trypsinogen was first hydrolysed by enterokinase under conditions which minimize autocatalytic activation. L-benzoyl-arginine paranitroanilide was then added and split to paranitroaniline by the trypsin so formed. Liberated paranitroalinine was diazotized and converted by the Bratton-Marshall reagent (N-naphthyl ethylene diamine) to an azodye, with maximum absorption at 550 nm. This method of determination was found to be six times more sensitive than the direct p-nitroaniline determination method. 36 determinations can be made hourly.
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PMID:An automated continuous flow procedure for the determination of enterokinase. 4 Jul 19

Interactions between trypsin and each of five dansyl-arginine derivatives, dansyl-L-arginine methyl ester (L-DAME), dansyl-D-arginine methyl ester (D-DAME), dansyl-L-arginine amide (L-DAA), dansyl-L-arginine (L-DA), and dansyl-D-arginine (D-DA), are accompanied by a fluorescence intensity change which can be followed by the stopped-flow method. These compounds are substrates or products in trypsin-catalyzed hydrolysis reactions. All of these compounds, except L-DAA, show a considerable fluorescence intensity increase in the reaction with trypsin. The observed rate constant, tau obsd -1, for the initial fluorescence intensity enhancement in the reaction between trypsin and D-DAME yields a typical hyperbolic curve when the rate is plotted as a function of the ligand concentration. This result is consistent with a two-step mechanism (1) in which a fast bimolecular association process is followed by a slower unimolecular isomerization process. The isomerization process may be considered to be associated with a conformational change of the enzyme molecule, induced by the formation of the enzyme-substrate complex (1). The rate of the isomerization process depends on pH. The rates obtained for L-DAME and D-DAME increase linearly with decrease of the hydrogen ion concentration in the pH range below neutral.
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PMID:Presteady state kinetics of trypsin-catalyzed hydrolyses of dansyl-arginine derivatives. 4 34

The synthesis of the protected duopentacontapeptide corresponding to the entire amino acid sequence I-52 of porcine pancreatic secretory trypsin inhibitor II (Kazal type) is described. The benzyloxycarbonyltetradecapeptide tert-butyloxycarbonylhydrazide (sequence 1-14) was selectively deblocked with trifluoroacetic acid and used to acylate, by the azide procedure, the peptide free base corresponding to the sequence 15-52. The isolated material was purified by ion exchange chromatography and the protecting groups were removed by successive treatments with anhydrous hydrogen fluoride, 1 M piperidine and mercuric acetate. F02M phosphate buffer, pH8. Determination of the inhibitory capacity indicated that the synthetic material is about 50% effective, at 30:1 inhibitor:trypsin molar ratio in inhibiting the tryptic hydrolysis of Nalpha-benzoyl-DL-arginine-4-nitroanilide. Full inhibition was achieved at a higher inhibitor:trypsin molar ratio. The stability constants and the standard free energy of binding of the complex between trypsin and the synthetic inhibitor have been determined.
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PMID:Studies on trypsin inhibitors. Part IX. Synthesis and trypsin inhibitory activity of the duopentacontapeptide corresponding to the amino acid sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal). 4 25

Porcine plasmin (EC 3.4.21.7) is obtained from plasminogen activated by human urokinase. This enzyme can bind, in an equimolecular ratio, to an alpha2-macroglobulin isolated from porcine serum. The number of active sites of plasmin has been determined through a burst titration of nitroaniline during the presteady-state hydrolysis of an amide substrate (N-alpha-carbobenzoxy-L-arginine-p-nitroanilide). The kinetic constants relative to a very sensitive ester substrate (N-alpha-carbobenzoxy-L-lysine nitrophenylester) hydrolysis have been measured. The binding of plasmin to alpha2-macroglobulin results in a complete inhibition of proteolytic activity, a reduction of active sites number and a decrease of esterolytic activity towards this substrate. In the complex, the residual activity (about 60%) is protected from protein inhibitors. Absorbance difference spectra show that 1 mol of alpha2-macroglobulin binds 1 mol of plasmin and 2 mol of trypsin. When plasmin is first bound to alpha2-macroglobulin, only 1 mol of trypsin can gain access tothe second site without removing the plasmin, showing that a steric hindrance is implicated in the inhibition performed by alpha2-macroglobulin binding.
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PMID:[Study of the complex between porcine plasmin and alpha2-macroglobulin (author's transl)]. 5 8

Proteases capable of activating procollagenase from gingiva and from fibroblast and macrophage monolayer cultures were harvested from homogenates of canine tumor mast cells. The mast cell proteases lysed casein and Azocoll but not native collagen. In low salt concentrations the enzymes existed at high molecular weight complexes, which were dissociated by increasing the salt concentration above 1.0 M (NaCl, KCl). Gel filtration in 1.4 M KCl separated the protease activity into three peaks, all of which activated procollagenase. Two of the enzymes showed substrate specificities (hydrolysis of p-tosyl-L-arginine methyl ester and benzoyl-tyrosine ethyl ester) and reactive center reactivities similar to pancreatic trypsin and chymotrypsin. Based on gel filtration, apparent molecular weights of 160 000 (p-tosyl-L-arginine methyl ester esterase), 90 000 (main procollagenase activator) and 36 000 benzoyl-tyrosine ethyl ester esterase) were determined. Activation of procollagenase resulted in a 18-20 000 decrease of the molecular weight. The activation was directly related to the amount of activator added within certain limits. Further addition of activator resulted in proteolytic inactivation of collagenase.
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PMID:Activation of fibroblast procollagenase by mast cell proteases. 5 9

Appropriately fixed preparations stained by a modification of the Guard (1959) reaction for "sex chromatin" display selective staining of interphase chromatin and mitotic or meiotic chromosomes. This is a regressive staining method which seems to depend on the selective displacement of an acidic dye from less basic structures, and retention of the dye at more basic sites. The results obtained with the reaction can be controlled by the length of time that the preparations are "differentiated" in solutions containing phosphomolybdic and phosphotungstic acids (polyacids). After three- or four-hour exposures to polyacid solutions, all chromatin is stained. However, with longer differentiation, "condensed" chromatin can be stained preferentially. Of a number of fixatives investigated, only 10% formalin, ethanol-acetic acid (3:1), and Bouin's solution proved useful. Others resulted in diminished specificity or a total loss of selectivity. The most intense staining was obtained after formalin fixation. Less intense dyebinding was observed after fixation in 3:1 - probably due to extraction of some histone fractions-and the least amount of dye was bound in Bouin's-fixed chromatin - probably due to blockage of arginine residues by picric acid. The reaction was not affected by enzymatic removal of nucleic acids or the extraction of lipids. It was diminished by treatment with trypsin or weak acetylation, and it was completely prevented by strong acetylation, deamination, or extraction of basic proteins with HCl. The results presented suggest that the modified Guard (1959) procedure selectively demonstrates basic nucleoproteins. Further, by the use of regressive differentiation in polyacid solutions, the retention of dye in more condensed chromatin can be favored.
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PMID:Cytochemical evaluation of the Guard procedure a regressive staining method for demonstrating chromosomal basic proteins. I. Effects of fixation, blocking reactions, selective extractions, and polyacid "differentiation". 6 Mar 23


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