A mutant leucine aminopeptidase from Streptomyces cinnamoneus with enhanced l-aspartyl l-amino acid methyl ester synthetic activity

作者：Arima Jiro^*; Kono Mirai; Kita Manami; Mori Nobuhiro

来源：Biotechnology Letters, 2012, 34(6): 1093-1099.

DOI：10.1007/s10529-012-0877-8

• Aminopeptidase
• L-aspartyl-L-phenylalanine methyl ester
• Peptide bond formation
• Reverse reaction

l-Aspartyl l-amino acid methyl ester was synthesized using a mutant of a thermostable leucine aminopeptidase from Streptomyces cinnamoneus, D198 K SSAP, obtained in previously. A peptide of high-intensity sweetener, l-aspartyl-l-phenylalanine methyl ester, was selected as a model for demonstrating the synthesis of l-aspartyl l-amino acid methyl ester. The hydrolytic activities of D198 K SSAP toward l-aspartyl-l-phenylalanine and its methyl ester were, respectively, 74-fold and fourfold higher than those of wild type. Similarly, the initial rate of the enzyme for l-aspartyl-l-phenylalanine methyl ester synthesis was over fivefold higher than that of wild-type SSAP in 90% methanol (v/v) in a one-pot reaction. Furthermore, other l-aspartyl l-amino acid methyl esters were synthesized efficiently using D198 K SSAP. Results show that the substitution of Asp198 of SSAP with Lys is effective for synthesizing l-aspartyl l-amino acid methyl ester.

• 出版日期2012-6