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)

1. We studied the effect of hyperosmolarity on human isolated airways because a better understanding of the effect of hyperosmolarity on the human airway wall may improve insight into the pathophysiology of hyperosmolarity-induced bronchoconstriction in asthma. 2. In cartilaginous bronchial rings dissected from fresh human lung tissue, hyperosmolar krebs-Henseleit buffer (450 mosM, extra sodium chloride added) evoked a biphasic response: a rapid relaxation phase (peak after 5.0 +/- 0.3 min) followed by a slow contraction phase (peak after 25.4 +/- 0.8 min). 3. With the histamine (H1) receptor antagonist mepyramine, the contraction phase was reduced to 41.2% of the control value (P less than 0.001), with atropine to 50.0% (P less than 0.01), with the local anaesthetic lignocaine to 48.7% (P less than 0.05) and with mepyramine together with atropine to 19.2% (P less than 0.001). 4. With the inhibitor of neutral metalloendopeptidase, phosphoramidon, the contraction phase increased to 128.0% of the control value (P less than 0.05) and after removal of the epithelium to 131.8% (P less than 0.05). 5. Indomethacin, the leukotriene C4/D4 (LTC4/D4) antagonist FPL 55712 or the blocker of nerve conduction, tetrodotoxin, had no effect on the contractile phase. 6. The relaxation phase was not altered by any of these drugs nor by epithelial denudation. The relaxation phase was also unchanged in the presence of alpha-chymotrypsin, which degrades muscle relaxing peptides such as vasoactive intestinal peptide. 7. Hyperosmolar buffer slightly increased the sensitivity and maximal response to methacholine as well as the cholinergic twitch to electric field stimulation. 8. We conclude that hyperosmolarity releases acetylcholine, histamine and neuropeptides in the human airway wall in sufficient quantities to contract airway smooth muscle. This release itself or its effect on airway muscle is modulated by the airway epithelium. The mechanism of the relaxation phase may be an unknown smooth muscle relaxing substance or a direct effect on the airway muscle, related to ion fluxes.
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PMID:Effects of hyperosmolarity on human isolated central airways. 185 21

Two active forms (Mr 45,000 and 28,000) of a metalloendopeptidase that digest proteoglycans and other extracellular matrix components of connective tissues have previously been purified from rheumatoid synovial cells and characterized [Okada, Nagase & Harris (1986) J. Biol. Chem. 261, 14245-14255]. To study the mechanisms of activation the precursor of this metalloendopeptidase has now been purified. The final products are homogeneous on SDS/polyacrylamide-gel electrophoresis and identified as a set of zymogens of Mr 57,000 and 59,000, in which the latter form is probably the product of post-translational glycosylation of the Mr 57,000 zymogen, as it binds to concanavalin A. The zymogen can be activated by trypsin, chymotrypsin, plasma kallikrein, plasmin and thermolysin, but not by thrombin. Although the activated metalloendopeptidase is further degraded by trypsin, plasma kallikrein and thermolysin during a prolonged incubation, it is relatively stable against plasmin and chymotrypsin. Activation with 4-aminophenylmercuric acetate is dependent on its concentration. It requires the reaction with the zymogen, possibly through thiol groups, and the continued presence of the agent. During this treatment the zymogen undergoes a sequential processing; first it becomes active without changing its apparent molecular mass, and then it is processed to low-Mr species of Mr 46,000, 45,000 (HMM) and 28,000 (LMM). The rate of conversion of the precursor into an initial intermediate of Mr 46,000 follows first-order kinetics (t1/2 2.0 h with 1.5 mM-4-amino-phenylmercuric acetate at 37 degrees C) and is independent of the initial concentration of the zymogen or the presence of up to a 676-fold molar excess of substrate, whereas the generation of HMM and LMM species is affected by these parameters. These results indicate that activation of the prometalloendopeptidase by an organomercurial compound is initiated by the molecular perturbation of the zymogen that results in conversion into the 46,000-Mr intermediate by an intramolecular action; the subsequent processing of this intermediate in HMM and LMM species is a bimolecular reaction. In vivo it is probable that the precursor of this metalloendopeptidase is activated either by direct limited proteolysis by tissue or plasma endopeptidases, or, alternatively, by factors that cause certain conformational changes in the zymogen molecule.
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PMID:The precursor of a metalloendopeptidase from human rheumatoid synovial fibroblasts. Purification and mechanisms of activation by endopeptidases and 4-aminophenylmercuric acetate. 305 16

Three proteolytic enzymes-the metalloproteinase, SFMP, and two serine proteinases, SFSP and SFTP-have been isolated and purified from the culture fluid of Streptomyces fradiae using chromatography on bacitracin-silochrome, bacitracin-Sepharose, DEAE-cellulose and fractionation by ammonium sulfate. Study of physico-chemical and functional properties of the enzymes and structural analysis revealed that SFMP is a cysteine-containing metalloendopeptidase with M(r) of 36 kDa, has a peak activity for synthetic substrates at pH 7.0-7.5 and at 60-65 degrees C and is stable at pH 7.0-9.0. The serine proteinase SFSP is related to subtilisin-like enzymes, has a M(r) of 29 kDa and a pH optimum at 7.5-8.5 at temperature up to 50 degrees C. The proteinase is stable at pH 4.0-9.0 and retains 30% of its activity at 70 degrees C. The other serine proteinase, SFTP, has a M(r) of 26 kDa and is related to trypsin-like enzymes. Its activity for synthetic substrates of trypsin is maximal at pH 6.8-8.8 at 50 degrees C. The enzyme is stable at pH 4.5-8.5 and at temperature below 50 degrees C. It has been shown that Streptomyces fradiae, like Streptomyces griseus and other Streptomycetes, possesses an ability to secrete serine proteinases (SFSP and SFTP) related to two evolutionally distinct families of serine proteinases, i.e., subtilisin and chymotrypsin families. SFMP and SFSP have been isolated and characterized for the first time.
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PMID:[Proteolytic enzymes from Streptomyces fradiae: a metalloendopeptidase, subtilisin-like, and trypsin-like proteinases]. 871 99

Phospholipase A2-I (PLA2-I) was isolated from Agkistrodon bilineatus venom by Nikai (Nikai et al., 1993). The amino acid sequence of the phospholipase A2-I was determined by the Edman sequencing procedure of peptides derived from digests utilizing cyanogen bromide, clostripain, metalloendopeptidase, chymotrypsin, and Staphylococcus aureus V8 protease. In the reduced state, purified phospholipase A2's molecular weight was determined to be 14,000 as demonstrated by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Purified PLA2-I also contained 1 mol of Ca per mol of protein and consists of 123 amino acid residues resulting in a calculated molecular weight of 14,133. Both phospholipase and lethal activities were found to be inhibited by bromophenacyl bromide, suggesting that the histidine residue is involved in this activity. Also there was an increase in the creatine kinase activity of mice serum, which is an indicator that PLA2-I is involved in muscle damage.
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PMID:Primary structure and pathological study of phospholipase A2-I from Agkistrodon bilineatus (common cantil) venom. 1200 14

AdpA in the A-factor regulatory cascade in Streptomyces griseus activates a number of genes required for secondary metabolism and morphological differentiation, forming an AdpA regulon. The Streptomyces subtilisin inhibitor (SSI) gene, sgiA, in S. griseus was transcribed in response to AdpA, showing that sgiA is a member of the AdpA regulon. AdpA bound a single site upstream of the sgiA promoter at approximately position -70 with respect to its transcriptional start point. Mutational analysis of the AdpA-binding site showed that the AdpA-binding site was essential for transcriptional activation. Mutants in which sgiA was disrupted had higher trypsin, chymotrypsin, metalloendopeptidase, and total protease activities than the wild-type strain, which showed that SgiA modulated the activities of these extracellularly produced proteases. Because a number of genes encoding chymotrypsins, trypsins, and metalloendopeptidases, most of which are SSI-sensitive proteases, are also under the control of AdpA, the A-factor regulatory cascade was thought to play a crucial role in modulating the extracellular protease activities by triggering simultaneous production of the proteases and their inhibitor at a specific timing during growth. Mutants in which sgiA was disrupted grew normally and formed aerial hyphae and spores with the same time course as the wild-type strain. However, exogenous addition of purified SgiA to substrate mycelium grown on agar medium resulted in a delay in aerial mycelium formation, indicating that SgiA is involved in aerial hypha formation in conjunction with proteases.
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PMID:Control of the Streptomyces Subtilisin inhibitor gene by AdpA in the A-factor regulatory cascade in Streptomyces griseus. 1692 87

Increased placental release of soluble VEGF receptor-1 (sFlt-1) is believed to play an important role in the pathogenesis of preeclampsia (PE). Although the reason for increased placental sFlt-1 release in PE is unknown, proteolytic effect has been proposed as one of the mechanisms that mediate sFlt-1 release in the placenta. In this study, using various protease inhibitors, we tested the possible role of proteases in sFlt-1 release by human placenta. Villous explants from normal term placentas were incubated with various protease inhibitors including serine protease inhibitors (PMSF, aprotini, and specific chymotrypsin inhibitor (CI)), cysteine protease inhibitor E-64, metalloendopeptidase inhibitor PAD, and universal metalloprotease (ADAM) inhibitor PTM. Culture medium was collected and measured for sFlt-1 by ELISA. Our results showed that villous tissue treated with CI and PTM produced significantly less sFlt-1 than those of controls. PMSF, aprotini, E-64, and PAD had no effect on sFlt-1 release. We further examined chymotrypsin-like protease/chymase and ADAM10 expressions in tissue sections from normal and PE placentas by immunohistochemistry. We found that immunostaining for chymase and ADAM10 was significantly increased in the layer of syncytiotrophoblasts in PE placentas compared to normal placentas. These results suggest chymotrypsin-like serine protease and ADAM10, but not cysteine protease and metalloendopeptidase, may play a role in inducing sFlt-1 release in PE placentas.
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PMID:Proteases and sFlt-1 release in the human placenta. 2043 67

Through processing peptide and protein C termini, carboxypeptidases participate in the regulation of various biological processes. Few tools are however available to study the substrate specificity profiles of these enzymes. We developed a proteome-derived peptide library approach to study the substrate preferences of carboxypeptidases. Our COFRADIC-based approach takes advantage of the distinct chromatographic behavior of intact peptides and the proteolytic products generated by the action of carboxypeptidases, to enrich the latter and facilitate its MS-based identification. Two different peptide libraries, generated either by chymotrypsin or by metalloendopeptidase Lys-N, were used to determine the substrate preferences of human metallocarboxypeptidases A1 (hCPA1), A2 (hCPA2), and A4 (hCPA4). In addition, our approach allowed us to delineate the substrate specificity profile of mouse mast cell carboxypeptidase (MC-CPA or mCPA3), a carboxypeptidase suggested to function in innate immune responses regulation and mast cell granule homeostasis, but which thus far lacked a detailed analysis of its substrate preferences. mCPA3 was here shown to preferentially remove bulky aromatic amino acids, similar to hCPA2. This was also shown by a hierarchical cluster analysis, grouping hCPA1 close to hCPA4 in terms of its P1 primed substrate specificity, whereas hCPA2 and mCPA3 cluster separately. The specificity profile of mCPA3 may further aid to elucidate the function of this mast cell carboxypeptidase and its biological substrate repertoire. Finally, we used this approach to evaluate the substrate preferences of prolylcarboxypeptidase, a serine carboxypeptidase shown to cleave C-terminal amino acids linked to proline and alanine.
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PMID:Proteome-derived peptide libraries to study the substrate specificity profiles of carboxypeptidases. 2362 May 45