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)

Purified human serum butyrylcholinesterase, which exhibits cholinesterase, aryl acylamidase, and peptidase activities, was cross-reacted with two different monoclonal antibodies raised against human serum butyrylcholinesterase. All three activities were immunoprecipitable at different dilutions of the two monoclonal antibodies. At the highest concentration of the antibodies used, nearly 100% of all three activities were precipitated, and could be recovered to 90-95% in the immunoprecipitate. The peptidase activity exhibited by the purified butyrylcholinesterase was further characterized using both Phe-Leu and Leu-enkephalin as substrates. The pH optimum of the peptidase was in the range of 7.5-9.5 and the divalent cations Co2+, Mn2+, and Zn2+ stimulated its activity. EDTA and other metal complexing agents inhibited its activity. Thiol agents and -SH group modifiers had no effect. The serine protease inhibitors, diisopropylfluorophosphate and phenyl methyl sulfonyl fluoride, did not inhibit. When histidine residues in the enzyme were modified by diethylpyrocarbonate, the peptidase activity was not affected, but the stimulatory effect of Co2+, Mn2+, and Zn2+ disappeared, suggesting the involvement of histidine residues in metal ion binding. These general characteristics of the peptidase activity were also exhibited by a 50 kD fragment obtained by limited alpha-chymotrypsin digestion of purified butyrylcholinesterase. Under all assay conditions, the peptidase released the two amino acids, leucine and phenylalanine, from the carboxy terminus of Leu-enkephalin as verified by paper chromatography and HPLC analysis. The results suggested that the peptidase behaved like a serine, cysteine, thiol-independent metallopeptidase.
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PMID:The peptidase activity of human serum butyrylcholinesterase: studies using monoclonal antibodies and characterization of the peptidase. 842 27

Peptidase sequences were analysed in randomly picked clones from cDNA libraries of the anterior or posterior midgut or whole larvae of the yellow mealworm, Tenebrio molitor Linnaeus. Of a total of 1528 sequences, 92 encoded potential peptidases, from which 50 full-length cDNA sequences were obtained, including serine and cysteine proteinases and metallopeptidases. Serine proteinase transcripts were predominant in the posterior midgut, whereas transcripts encoding cysteine and metallopeptidases were mainly found in the anterior midgut. Alignments with other proteinases indicated that 40% of the serine proteinase sequences were serine proteinase homologues, and the remaining ones were identified as either trypsin, chymotrypsin or other serine proteinases. Cysteine proteinase sequences included cathepsin B- and L-like proteinases, and metallopeptidase transcripts were similar to carboxypeptidase A. Northern blot analysis of representative sequences demonstrated the differential expression profile of selected transcripts across five developmental stages of Te. molitor. These sequences provide insights into peptidases in coleopteran insects as a basis to study the response of coleopteran larvae to external stimuli and to evaluate regulatory features of the response.
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PMID:Sequence analysis and molecular characterization of larval midgut cDNA transcripts encoding peptidases from the yellow mealworm, Tenebrio molitor L. 1765 Dec 35

In this study we purified and characterized a fibrinolytic protease from the mycelia of Perenniporia fraxinea. The apparent molecular mass of the purified enzyme was estimated to be 42kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), fibrin zymography and size exclusion using fast protein liquid chromatography (FPLC). The first 20 amino acid residues of the N-terminal sequence were ASYRVLPITKELLPPEFFVA, which shows a high degree of similarity with a fungalysin metallopeptidase from Coprinopsis cinerea. The optimal reaction pH value and temperature were pH 6.0 and 35-40 degrees C, respectively. Results for the fibrinolysis pattern showed that the protease rapidly hydrolyzed the fibrin alpha-chain followed by the beta-chain. The gamma-gamma chains were also hydrolyzed, but more slowly. The purified protease effectively hydrolyzed fibrinogen, preferentially digesting the Aalpha-chains of fibrinogen, followed by Bbeta- and gamma-chains. We found that protease activity was inhibited by Cu(2+), Fe(3+), and Zn(2+), but enhanced by the additions of Mn(2+), Mg(2+) and Ca(2+) metal ions. Furthermore, the protease activity was inhibited by EDTA, and it was found to exhibit a higher specificity for the chromogenic substrate S-2586 for chymotrypsin, indicating that the enzyme is a chymotrypsin-like metalloprotease. The mycelia of P. fraxinea may thus represent a source of new therapeutic agents to treat thrombosis.
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PMID:Purification and characterization of fibrinolytic metalloprotease from Perenniporia fraxinea mycelia. 1855 Mar 50