b-Alanyl peptide synthesis by Streptomyces S9 aminopeptidase

• Published in: Journal of biotechnology Vol. 147; no. 1; pp. 52 - 58
• Main Authors: Arima, Jiro, Morimoto, Masazumi, Usuki, Hirokazu, Mori, Nobuhiro, Hatanaka, Tadashi
• Format: Journal Article
• Language: English
• Published: 03.05.2010
• Subjects: Biotechnology; Catalysis; Catalysts; Conversion ratio; Derivatives; Esters; Peptides; Streptomyces; Synthesis
• DOI: 10.1016/j.jbiotec.2010.03.007
• ISSN: 0168-1656

Synthesis of b-alanine (b-Ala) containing dipeptide using S9 aminopeptidase from Streptomyces thermocyaneoviolaceus NBRC14271 (S9AP-St) was demonstrated with b-Ala-benzyl ester (-OBzl) and various l-aminoacyl derivatives. For synthesis of b-Ala-containing dipeptide, b-Ala-OBzl was used preferentially as the acyl donor for S9AP-St, producing synthesized dipeptides having b-Ala-Xaa structure. In contrast, engineering of S9AP-St into "transaminopeptidase" by substitution of catalytic Ser with Cys - designated as aminolysin-S - produced only dipeptides having Xaa-b-Ala structure. Investigation of the specificity of S9AP-St toward acyl acceptors showed that S9AP has a broad substrate specificity toward various aminoacyl derivatives. Furthermore, S9AP-St produced carnosine methyl ester (-OMe) with a conversion ratio of b-Ala-OBzl to carnosine-OMe that was greater than 30%.