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)

Further evidence is presented that the acrosomal proteinase acrosin exists as a zymogen precursor in freshly ejaculated boar spermatozoa. Autoactivation of proacrosin to acrosin takes place optimally at slightly alkaline pH and in the presence of calcium ions. Activation is considerably accelerated by catalytic amounts of trypsin or highly purified acrosin. A significant acceleration of the activation is also achieved by porcine pancreatic and urinary kallikrein, whereas chymotrypsin, plasmin, thrombin or urokinase showed no effect. Activation can be inhibited by p-amino-benzamidine and p-nitrophenyl p'-guanidino-benzoate. Electrophoretic analysis at different stages of activation revealed that during this process various molecular forms of acrosin are produced, apparently by limited proteolysis.
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PMID:Multiple forms of boar acrosin and their relationship to proenzyme activation. 0 66

Two proteinases (2A and 2B) purified from the granular fraction of horse blood leucocytes degrade casein (Km values 12.8 and 6mg/ml respectively) with maximum activity at pH 7.4 and in the presence of 2m-urea. Urea-denatured haemoglobin, fibrinogen, albumin and resorcin/fuchsin-stained elastin are digested at a slower rate. The enzymes hydrolyse synthetic substrates of elastase, N-benzyloxycarbonyl-L-alanine 4-nitrophenyl ester (Km 0.114 and 0.178 mM) and N-acetyl-tri-L-alanine methyl ester (Km 5.55 and 0.98 mM), but they do not hydrolyse synthetic substrates of trypsin, chymotrypsin and thrombin. The examined proteinases are completely inhibited by 2 mM-di-isopropyl phosphorfluoridate and show a sensitivity to butyl and octyl isocyanates similar to that of pancreatic elastase. The pH-dependence of their photoinactivation in the presence of Rose Bengal indicates the presence of histidine in the active centre. Proteinase 2A rather insensitive to iodination by IC1 as is pancreatic elastase, whereas proteinase 2B is totally inactivated after incorporation of five iodine atoms per enzyme molecule.
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PMID:Substrate specificity and modifications of the active centre of elastase-like neutral proteinases from horse blood leucocytes. 0 9

Some properties of protein inhibitor for trypsin (TI) from Act. janthinus 118 were studied. It was shown that TI has an antitrypsin activity within a wide pH range with a maximum at about 9,5. At 4 degrees and 20 degrees C TI is stable for 24 hours within the pH range of 6,0--11,0. At 100 degrees C TI is more stable in the slightly acid region of pH than at neutral or alkaline conditions. Trypsin and chymotrypsin inactivate the inhibitor for 8 hours. TI inhibits trypsin, fibrinolysin, subtilisin, pronase and terrilytin, but have no effect on chymotrypsin, thrombin, papain and pepsin. The dissociation constants for the trypsin-inhibitor complex were found to be 1,7.10-8 M, 4,1.10-9 M and 2,4.10-10 M, with casein, p-nitroanilide benzoylarginine and tosylarginine methyl ester used as substrates, respectively. The corresponding dissociation rate constants for the subtilisin-inhibitor complex were equal to 1.10-9 M and 4.10-10 M with casein and carbobenzoxy-L-alanyl-L-alanyl-L-leucin p-nitroanilide used as substrates, respectively.
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PMID:[Stability and specificity of extracellular protein inhibitor for trypsin from Actinomyces janthinus 118]. 3 28

Analysis of platelet membrane proteins and glycoproteins by SDS polyacrylamide gel electrophoresis was carried out before and after treatment with thrombin. Extended incubation with thrombin (in the presence of EDTA or adenosine, which inhibit aggregation) produced extensive changes in the bands observed. With incubation times of a few minutes however, the changes were restricted to a glycopeptide, GP IV (approx. 90,000 Daltons) and one or two polypeptides of low molecular weight, in particular polypeptide 16 (approx. 23,000 Daltons). At 0--3 degrees C only polypeptide 16 was still hydrolyzed. Chymotrypsin, which does not activate platelets, attacked glycopeptides I, II, III but no changes were apparent in GP IV and polypeptide 16. When chymotrypsin-treated platelets were further incubated with thrombin, only GP IV and one to two low molecular weight polypeptides, especially polypeptide 16, were affected. As polypeptide 16 appears to be an integral membrane component it is possible that it, either by itself or in combination with GP IV, represents the primary thrombin substrate involved in platelet activation. Aggregated IgG, which also activates platelets, does not modify the membrane glycoproteins but does change the low molecular weight region in particular band 16.
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PMID:Effects of thrombin, chymotrypsin and aggregated gamma-globulins on the proteins of the human platelet membrane. 7 80

Alpha2-M (alpha2-macroglobulin) was purified from human plasma by two different procedures. As well as having no detectable impurities by the usual criteria for testing the homogeneity of protein preparations, these alpha2M preparations showed a single component, after reduction in urea, of 185000 daltons by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The molecular weight of the alpha2M was found to be 718000 by sedimentation equilibrium experiments using the gravimetrically determined -v of 0.731 ml/g. The interaction of several proteinases with alpha2M was studied by using a novel discontinuous polyacrylamide-gel system, which showed clear separation of the enzyme-complexed alpha2M from the free alpha2M. These studies indicated that urokinase, as well as trypsin, chymotrypsin, plasmin and thrombin forms complexes with alphaM. The cleavage of the 185000-dalton subunit to a 85000-dalton species on interaction of trypsin with alpha2M was demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis after reduction of the alpha2M-trypsin complex in urea. The amino acid composition, carbohydrate content, absorption coefficient at 280 nm, the specific refractive increment and the sedimentation coefficient for these alpha2M preparations were measured. The stability of the trypsin-binding activity of the alpha2M preparations was also studied under several storage situations.
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PMID:Physical and chemical properties of human plasma alpha2-macroglobulin. 8 Feb 17

The trypsin inhibitor of bovine colostrum was isolated by affinity chromatography, and impurities removed by trichloroacetic acid precipitation. The inhibitor showed electrophoretic microheterogeneity which was not due to sialic acid content. It inhibited bovine and rat trypsin, showed weak inhibition of bovine chymotrypsin and was inactive against rat chymotrypsin and bovine renin, kallikrein, thrombin and trypsinogen. The dynamics of secretion of the inhibitor in the first 8 milkings post-partum were very similar to those of colostral immunoglobulins.
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PMID:Isolation and properties of bovine colostral trypsin inhibitor. 10 61

Trypsin, thrombin, fibrinolysin, papain, chymothrypsin and urokinase were immobilized on aminopolystyrene resin by the reaction of diazocoupling. An activation of prothrombin and plasminogen and also hydrolysis of fibrin by immobilized enzymes were studied. The immobilized enzymes hydrolyzed N-benzoyl-1-arginine ethyl ester and L-tyrosine ethyl ester. The only preparation of immobilized thrombin possessed the coagulational activity. After the covalent binding trypsin and plasmin maintained the capacity to cause a fibrinolysis. Immobilized trypsin, plasmin, papain, chymotrypsin and urokinase exhibited the fibrinolytic effect due to convertion of plasminogen into plasmin.
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PMID:[Blood coagulating properties of immobilized proteases]. 14 May 25

The primary structure of the human plasmin B-chain has been determined. It consists of 230 residues divided in three cyanogen bromide fragments: The amino-terminal 24 residues, the carboxy-terminal three residues and the middle 203 residues. Sequence detemination was performed on the tryptic and the chymotryptic peptides obtained from the main cyanogen bromide fragment of this chain. Owing to similarities between some of the overlapping chymotryptic peptides, two different sequences were possible from these results. However, since the homologies with the pancreatic serine proteases and also the B-chains of thrombin and factor XA are pronounced, the arrangement still could be settled. By peptic digestion of partially reduced and S-carboxymethylated B-chain it was shown that there are two interchain disulphide bridges, which connect the A and B-chains of plasmin, involving Cys-5 and Cys-105 from the B-chain. The intrachain disulphides in the B-chain seem to be situated exactly as in chymotrypsin as partly judged from homologies.
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PMID:Primary structure of the B-chain of human plasmin. 14 9

The inhibition of plasmin, (EC 3.4.21.7), thrombin (EC 3.4.21.5), trypsin (EC 3.4.21.4) and chymotrypsin (EC 3.4.21.1) by antiplasmin, the recently described fast-reacting plasmin inhibitor of human plasma, was studied. To determine the quantitative importance of antiplasmin relative to the other plasma protease inhibitors, enzyme inhibition assays were performed on whole plasma and on plasma specifically depleted in antiplasmin, after addition of excess enzyme. Plasmin was the only enzyme for which the inhibitory capacity of antiplasmin-depleted plasma was lower than that of normal plasma. To determine the affinity of the enzymes for antiplasmin, as compared to the other inhibitors, various amounts of enzymes were added to normal plasma and the formation of enzyme-antiplasmin complexes studied by crossed immunoelectrophoresis using specific antisera against antiplasmin. Plasmin and trypsin, but not thrombin or chymotrypsin formed complexes with antiplasmin. It is concluded that antiplasmin is the only fast-reacting plasmin inhibitor of human plasma. It is also a fast-reacting inhibitor of trypsin but only accounts for a very small part of the fast-reacting trypsin-inhibitory activity of plasma. This can be explained by the low concentration of antiplasmin (1 muM) in normal plasma, compared to the other inhibitors (e.g. alpha1-antitrypsin: 40-80 muM).
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PMID:The interaction in human plasma of antiplasmin, the fast-reacting plasmin inhibitor, with plasmin, thrombin, trypsin and chymotrypsin. 14 66

Inhibitory activities of alpha2-plasmin inhibitor against various proteases were investigated. The inhibitor promptly inhibited the esterolytic activity of alpha-chymotrypsin and progressively inhibited the esterolytic or amidolytic activities of bovine plasma kallikrein, bovine thrombin and bovine activated factor X. Heparin had no effect on the reaction of the inhibitor with thrombin or activated factor X. However, the inhibitor had no effect on the activities of human C-1-esterase, papain and snake venom kininogenase. On the basis of its rapid inhibition of kallikrein, alpha2-plasmin inhibitor is considered to exert some regulating effect on kallikrein activity in plasma.
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PMID:Inhibition of proteases in coagulation, kinin-forming and complement systems by alpha2-plasmin inhibitor. 14 28


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