title: Aminolytic reaction catalyzed by D-stereospecific amidohydrolases from Streptomyces spp.
abstract: From investigation of 2000 soil isolates, we identified two serine-type amidohydrolases that can hydrolyze d-aminoacyl derivatives from the culture supernatant of Streptomyces species 82F2 and 83D12. The enzymes, redesignated as 82F2-DAP and 83D12-DAP, were purified for homogeneity and characterized. Each enzyme had molecular mass of approximately 40 kDa, and each showed moderate stability with respect to temperature and pH. Among hydrolytic activities toward d-aminoacyl-pNAs, the enzymes showed strict specificity toward D-Phe-pNA, but showed broad specificity toward D-aminoacyl esters. The specific activity for D-Phe-pNA hydrolysis of 82F2-DAP was ten-fold higher than that of 83D12-DAP. As a second function, each enzyme showed peptide bond formation activity by its function of aminolysis reaction. Based on results of D-Phe-D-Phe synthesis under various conditions, we propose a reaction mechanism for D-Phe-D-Phe production. Furthermore, the enzymes exhibited peptide elongation activity, producing oligo homopeptide in a one-pot reaction. We cloned the genes encoding each enzyme, which revealed that the primary structure of each enzyme showed 30-60% identity with those of peptidases belonging to the clan SE, S12 peptidase family categorized as serine peptidase with d-stereospecificity.
authors.affiliation: Department of Agricultural, Biological, and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Arima
authors.forename: Hitomi
authors.initials: H
authors.lastname: Ito
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hatanaka
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mori
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D002384:Catalysis; D004151:Dipeptides / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013237:Stereoisomerism; D013302:Streptomyces / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D004151:Dipeptides; D005656:Fungal Proteins; D000581:Amidohydrolases