Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The proteolytic system of Bifidobacterium animalis subsp. lactis was analyzed, and an intracellular endopeptidase (PepO) was identified and characterized. This work reports the first complete cloning, purification, and characterization of a proteolytic enzyme in Bifidobacterium spp. Aminopeptidase activities (general aminopeptidases, proline iminopeptidase, X-prolyl dipeptidylaminopeptidase) found in cell extracts of B. animalis subsp. lactis were higher for cells that had been grown in a milk-based medium than for those grown in MRS. A high specific proline iminopeptidase activity was observed in B. animalis subsp. lactis. Whole cells and cell wall-bound protein fractions showed no caseinolytic activity; however, the combined action of intracellular proteolytic enzymes could hydrolyze casein fractions rapidly. The endopeptidase activity of B. animalis subsp. lactis was examined in more detail, and the gene encoding an endopeptidase O in B. animalis subsp. lactis was cloned and overexpressed in Escherichia coli. The deduced amino acid sequence for B. animalis subsp. lactis PepO indicated that it is a member of the M13 peptidase family of zinc metallopeptidases and displays 67.4% sequence homology with the predicted PepO protein from Bifidobacterium longum. The recombinant enzyme was shown to be a 74-kDa monomer. Activity of B. animalis subsp. lactis PepO was found with oligopeptide substrates of at least 5 amino acid residues, such as met-enkephalin, and with larger substrates, such as the 23-amino-acid peptide alpha s1-casein(f1-23). The predominant peptide bond cleaved by B. animalis subsp. lactis PepO was on the N-terminal side of phenylalanine residues. The enzyme also showed a post-proline secondary cleavage site.
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PMID:Enzymatic ability of Bifidobacterium animalis subsp. lactis to hydrolyze milk proteins: identification and characterization of endopeptidase O. 1633 35

Nodule extracts prepared from Glycine max var Woodworth possessed endopeptidase, aminopeptidase, and carboxypeptidase activities. Three distinct endopeptidase activities could be resolved by disc-gel electrophoresis at pH 8.8. According to their order of increasing electrophoretic mobility, the first of these enzymes hydrolyzed azocasein and n-benzoyl-l-Leu-beta-naphthylamide, while the second hydrolyzed n-benzoyl-l-Arg-beta-naphthylamine (Bz-l-Arg-betaNA), n-benzoyl-l-Arg-p-nitroanilide (Bz-l-Arg-pNA), and azocasein. The third endopeptidase hydrolyzed Bz-l-Arg-betaNA, Bz-l-Arg-pNA, and hemoglobin. Fractions of these enzymes extracted from electrophoresis gels were shown to have pH optima from 7.5 to 9.8. All of the endopeptidases were completely inhibited by diisopropylphosphorofluoridate, demonstrating that they were serine proteases.Aminopeptidase activity was measured using amino acyl-beta-naphthylamides. Electrophoresis of nodule extracts at pH 6.8 resolved the aminopeptidase activity of nodule extracts into at least four fractions based on mobility and on activities toward amino acyl-beta-naphthylamides. The major activity of two of the aminopeptidases was directed toward l-Leu- and l-Met-beta-naphthylamide, while the other two aminopeptidases exhibited broader specificity and were capable of hydrolyzing a large number of amino acyl-beta-naphthylamides. Two of the aminopeptidases extracted from electrophoresis gels were classified as thiol type enzymes, and all four aminopeptidases had neutral to basic pH optima.
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PMID:Peptidohydrolases of Soybean Root Nodules : IDENTIFICATION, SEPARATION, AND PARTIAL CHARACTERIZATION OF ENZYMES FROM BACTEROID-FREE EXTRACTS. 1666 22

One endopeptidase (EP1) and at least three aminopeptidases (AP1, AP2, and AP3) were discovered in the stroma of chloroplasts isolated from pea seedlings (Pisum sativum L.), and purified over 100-fold. EP1 requires added Mg(2+) or Ca(2+) for activity, may have an additional tightly bound metal atom, and is inhibited by sulfhydryl reagents but not by serine residue-directed inhibitors. It is reversibly inhibited by dithiothreitol. Its specificity is for the bond between two adjacent Ala or Gly residues. Its molecular mass is 93 kilodaltons, estimated on a gel filtration column. Aminopeptidase activities were detected with the aid of different amino acyl-beta-naphthylamides as substrates. They were resolved into at least three individual proteins by gel filtration and DEAE-cellulose chromatography, having apparent molecular masses of 269,000 (AP1), 84,000 (AP2), and 42,000 (AP3) daltons, respectively. Each has a unique specificity for substrates, with AP1 hydrolyzing only the Prolyl-beta-naphthylamide. None of the APs require added divalent cations for activity, but the possibility of a tightly bound metal function was suggested in AP2 and AP3 (not AP1) from effects of inhibitors. A probable sulfhydryl residue function was indicated for all three, from inhibition by p-hydroxymercuribenzoate and Zn(2+). All these peptidases had pH optima at 7.7.
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PMID:Neutral peptidases in the stroma of pea chloroplasts. 1666 64

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases (protein-degrading enzymes) have frequently been assayed in freshwater systems, but such studies have been limited to substrates for a single enzyme [leucyl aminopeptidase (Leu-AP)] out of more than 300 biochemically recognized peptidases. Here, we report kinetic measurements of extracellular hydrolysis of five substrates in 28 freshwater bodies in the Delaware Water Gap National Recreation Area in the Pocono Mountains (PA, United States) and near Knoxville (TN, United States), between 2013 and 2016. The assays putatively test for four aminopeptidases (arginyl aminopeptidase, glyclyl aminopeptidase, Leu-AP, and pyroglutamyl aminopeptidase), which cleave N-terminal amino acids from proteins, and trypsin, an endopeptidase, which cleaves proteins mid-chain. Aminopeptidase and the trypsin-like activity were observed in all water bodies, indicating that a diverse set of peptidases is typical in freshwater. However, ratios of peptidase activities were variable among sites: aminopeptidases dominated at some sites and trypsin-like activity at others. At a given site, the ratios remained fairly consistent over time, indicating that they are driven by ecological factors. Studies in which only Leu-AP activity is measured may underestimate the total peptidolytic capacity of an environment, due to the variable contribution of endopeptidases.
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PMID:Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains. 2955 61


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