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)

1. We have found that 'acid'-activation of inactive human plasma renin is a two-phase process. About 30% of activation occurs during dialysis to pH 3.3; the remaining 70% occurs at alkaline pH. 2. The 'alkaline phase' of activation has a pH optimum between 7.5 and 8.4. It is inhibited by unacidified plasma and by soya-bean or lima-bean trypsin inhibitors. 3. 'Cryoactivation' of inactive plasma renin, which occurs at -4 degrees C and alkaline pH, is also inhibited by soya-bean or lima-bean trypsin inhibitors and by the serine protease inhibitors diisopropylphosphorofluoridate and benzamidine. 4. Thus endogenous neutral serine proteases participate in the activation of inactive plasma renin in vitro. Their action is prevented in the circulation by inhibitors which are inactivated by acid or cold.
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PMID:Activation of inactive plasma renin: evidence that both cryoactivation and acid-activation work by liberating a neutral serine protease from endogenous inhibitors. 3 4

Protease-like activity which split plasminogen-free fibrin was demonstrated in 2 M KSCN extracts of the lung and spleen of conventional rats. The activity was virtually undetectable in tissue extracts from germ-free rats. The extracts from the conventional rat tissues split fibrin and fibrinogen remarkably at neutral pH, but not casein, when examined using fibrin, fibrinogen-agar and casein-agar plates. The fibrinolytic activity was inhibited by STI and DFP, indicating a serine protease nature. The activity was not inhibited by TLCK, t-AMCHA or dansyl-L-arginine-methylpiperidine amide (a selective synthetic thrombin inhibitor, OM189). It was neither activated nor inhibited by cysteine, KCN or iodoacetic acid. The results obtained indicate that the protease-like activity of the lung and spleen extracted with 2 M KSCN from conventional rats has properties which differ from those of trypsin, plasmin, plasminogen-activator, thrombin, and cathepsin A, B and C.
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PMID:Fibrinolytic activity of lung and spleen extracts observed in conventional but not in germ-free rats. 9 68

Rates of hydrolysis of the newly developed peptide chromogenic substrates S-2160 (N-Bz-Phe-Val-Arg-pNA, HCl), S-2238 (H-D-Phe-Pip-Arg-pNA, 2HCl), S-2222 (N-Bz-Ile-Glu-Gly-Arg-pNA, HCl), and S-2251 (H-D-Val-Leu-Lys-pNA, 2HCl) from AB Kabi Peptide Research and Chromozym TH (Z-Gly-Pro-Arg-pNA, HCl) from Pentapharm Limited were tested against highly purified preparations of human plasmin, bovine trypsin, human alpha thrombin, and bovine factor Xa. S-2160, S-2238, and Chromozym TH are sensitive to thrombin, Chromozym TH and S-2238 exhibiting a substantially greater sensitivity than S-2160. All 3 substrates are insensitive to factor Xa but hydrolyzed to varying degrees by plasmin and trypsin. In contrast, S-2222 is sensitive to Xa and insensitive to thrombin. S-2251 is relatively plasmin-specific, being resistant to the clotting enzymes thrombin and Xa. S-2251 exhibits even greater sensitivity to the SK-plasmin complex than to plasmin. In addition, the substrate Chromozym PK (N-Bz-Pro-Phe-Arg-pNA, HCl) was evaluated and found to be relatively specific for plasma kallikrein. Assays for antithrombin III and heparin using S-2222 as the substrate and factor Xa as the enzyme, plasma plasminogen and plasmin inhibitors using S-2251 as the substrate, and plasma prekallikrein and kallikrein inhibitors using Chromozym PK as the substrate have been developed. Synthetic peptides mimicking amino acid sequences adjacent to proteolytic activation cleavage of plasma serine protease precursors appear to be sensitive and relatively specific tools applicable to kinetical and clinical studies of these enzymes and their inhibitors.
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PMID:Serine protease specificity for peptide chromogenic substrates. 14 72

In this paper, we present the amino-terminal sequence of rat tonin, an endopeptidase responsible for the conversion of angiotensinogen, the tetradecapeptide renin substrate, or angiotensin I to angiotensin II. It is shown that isoleucine and proline occupy the amino- and carboxy-terminal residues respectively. The N-terminal sequence analysis permitted the identification of 34 out of the first 40 residues of the single polypeptide chain composed of 272 amino acids. These results showed an extensive homology with the sequence of many serine proteases of the trypsin-chymotrypsin family. This information, coupled with the slow inhibition of tonin by diisopropylfluorophosphate, classified this enzyme as a selective endopeptidase of the active serine protease family.
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PMID:N-Terminal amino acid sequence of rat tonin: homology with serine proteases. 21 93

The tumor promoter phorbol myristate acetate (PMA) induces the production of the serine protease plasminogen activator (PA) in cultures of normal chick embryo fibroblasts (CEF) and synergistically enhances PA production in Rous sarcoma virus-transformed chick embryo fibroblasts (RSVCEF). Following PMA treatment of serum-free RSVCEF cultures, PA induction is accompanied by distinct morphological changes, including enhanced cell clustering and the formation of dense cellular aggregates. These alterations in the morphology of the PMA-treated transformed cells are inhibited by several protease inhibitors, including leupeptin, NPGB, SBTI, benzamidine and DFP, the specific inhibitor of serine enzymes. A number of protease inhibitors are ineffective in preventing the PMA-induced morphological changes; these include inhibitors of trypsin, chymotrypsin, elastase, thrombin and, most importantly, plasmin. The use of a fluorescent substrate to assay PA directly demonstrated that the pattern of inhibiton of PA activity correlates exactly with the inhibition of morphological changes. The of 3H-DFP to label and characterize serine zymes in the culture fluid from PMA-treated cells further indicated that PA is the serine protease responsible for the morphological changes. Thus PA itself can catalytically alter cellular behavior in culture independent of plasminogen, until not its only known natural substrate.
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PMID:Phorbol ester-induced morphological changes in transformed chick fibroblasts: evidence for direct catalytic involvement of plasminogen activator. 22 74

Various serine proteases (e.g., trypsin, alpha-chymotrypsin, Pronase, and subtilisin) stimulate adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity in a membrane-enriched fraction of the rat ovary. Maximum stimulation is observed at protease concentrations ranging from 3 to 10 mug/ml. Higher protease concentrations inhibit ovarian adenylate cyclase in a dose-dependent manner. Protease stimulation causes a 6- to 8-fold increase in adenylate cyclase activity, which is comparable to the stimulation observed with human chorionic gonadotropin. Combinations of trypsin plus hormone or trypsin plus NaF stimulate ovarian adenylate cyclase activity to a greater extent than does any one of these alone. The mechanism of protease stimulation of adenylate cyclase involves limited proteolysis because zymogen precursors fail to activate the cyclase as does trypsin pretreated with trypsin inhibitors. Unlike cholera toxin, the serine protease stimulation is immediate (within the first 5 min) and requires no additional factors (e.g., NAD(+)). It is unlikely that protease stimulation of adenylate cyclase results from a proteolytic modification of the hormone receptor on the cell surface, because of the additive effects noted above and because protease stimulation is also observed in ovaries desensitized to hormone that lack this hormone receptor. Results with Lubrol-treated membranes also suggest that proteolytic enzymes do not directly activate the catalytic subunit of the cyclase or unmask new catalytic sites because the protease effect (like hormonal stimulation) is abolished by the detergent, whereas fluoride stimulation is enhanced. Other data suggest that serine protease and chorionic gonadotropin stimulation of adenylate cyclase result from activation of a membrane protease that then regulates adenylate cyclase in the ovary.
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PMID:Proteolytic enzyme activation of rat ovarian adenylate cyclase. 27 Jul 17

Involvement of serine protease-activation in the generation of cytoplasmic factor(s) that induced NHP-specific protein kinase activity in nuclei in anti-Ig-stimulated cells was described. DFP or PMSF with anti-Ig inhibited the induction of cytoplasmic factor(s), whereas pretreatment of cells with DFP or PMSF without anti-Ig did not show any inhibitory effect on anti-Ig-induced generation of cytoplasmic factor(s). TAME or BAME with anti-Ig inhibited the generation of cytoplasmic factor(s) and the simultaneous addition of TAME or BAME with DFP protected the generation of cytoplasmic factor(s) against the inhibitory effect of DFP, showing the involvement of trypsin-like, arginine-type serine protease in anti-Ig-induced generation of cytoplasmic factor(s). Anti-Ig-stimulated membrane preparations induced cytoplasmic factor(s) in normal cytoplasm. The m.w. of precursor proteins present in resting B cells and active cytoplasmic factor(s) were approximately 150,000 and 45,000, respectively. These results showed that anti-Ig-activated membrane-bound serine protease split precursor proteins in resting B cells into active cytoplasmic factor(s) responsible for signal transmission.
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PMID:Involvement of anti-Ig-activated serine protease in the generation of cytoplasmic factor(s) that are responsible for the transmission of Ig-receptor-mediated signals. 31 62

Both low- and high-molecular-weight inhibitors of serine proteases were found to inhibit chemotaxis by human polymorphonuclear leukocytes totally at widely varying concentrations. Synthetic low-molecular-weight substrates with trypsin-like or chymotrypsin-like specificity were also shown to be potent inhibitors of chemotaxis. Chemotactic inhibition was reversible except with a titrant for the active site of a serine protease. N-acetyl-L-tyrosine ethyl ester was found to be a suitable substrate for measuring protease activity of polymorphonuclear leukocyte. Concentrations of the various protease inhibitors that caused 100% chemotactic inhibition caused 80%-100% inhibition of protease activity of polymorphonuclear leukocytes.
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PMID:The effect of some protease substrates and inhibitors on chemotaxis and protease activity of human polymorphonuclear leukocytes. 39 41

"Group-specific" protease (GSP) is a serine protease, obtained from rat small intestine, which preferentially inactivates the apo forms of certain pyridoxal phosphate requiring enzymes. The enzyme contains 224 amino acid residues in a single polypeptide chain and three disulfide bonds. In the present work the covalent structure has been determined and its homologous relationship to those of chymotrypsin, trypsin, and elastase has been established (approximately 33% identity with each). The residues forming the "charge-relay" system of the active site of chymotrypsin (His-57, Asp-102, and Ser-195) are found in corresponding regions in GSP, whereas an alanyl residue at position 176 of GSP corresponds to a residue which participates in the primary substrate binding site in serine proteases (Asp-177 in trypsin; Ser-189 in chymotrypsin). Three disulfide bonds in GSP occur in similar positions in chymotrypsin, trypsin, and elastase. However, GSP lacks a disulfide bond which is present in all known serine proteases (linking Cys-191 to Cys-220 in chymotrypsin). In view of the close proximity of this bond to both the primary and the antiparallel binding sites of various serine proteases, it is likely that its absence in GSP is related to the substrate specificity of this enzyme. It is concluded that GSP diverged from a common ancestor preceding chymotrypsin but following trypsin.
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PMID:Covalent structure of a group-specific protease from rat small intestine. Appendix: crystallographic data for a group specific protease from rat intestine. 62 33

Plasminogen activator activity was detected in human gynecologic specimens using a synthetic fluorogenic peptide substrate assay and confirmed by an 125I-labeled fibrin plate assay. Epithelial cells in these samples contain enzymatic activity that biochemically resembles both the well-characterized plasminogen activator, urokinase, and the less-specific plasminogen activator, trypsin. Inhibition of the cervical cell activity by diisopropylfluorophosphate and p-nitrophenyl-p'-guanidinobenzoate demonstrates that, like urokinase and trypsin, this plasminogen activator is also a serine protease. Polyacrylamide gel electrophoresis of plasminogen that had been incubated with cervical cells indicated the same mechanism of plasminogen activation as exhibited by urokinase. We attempted to correlate plasminogen activator activity of each sample with cytomorphologic diagnosis. Three of the four dysplastic samples analyzed showed higher plasminogen activator activity than did the normal samples.
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PMID:Characterization of plasminogen activator in human cervical cells. 65 74


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