An aminoacylase activity from <i>Streptomyces ambofaciens</i> catalyzes the acylation of lysine on α‐position and peptides on N‐terminal position

Abstract

The presence of aminoacylase activities was investigated in a crude extract of <i>Streptomyces ambofaciens</i> ATCC23877. First activities catalyzing the hydrolysis of N-α or ε-acetyl-L-lysine were identified. Furthermore, the acylation of lysine and different peptides was studied and compared with results obtained with lipase B of <i>Candida antarctica</i> (CALB). Different regioselectivities were demonstrated for the two classes of enzymes. CALB was able to catalyze acylation only on the ε-position whereas the crude extract from <i>S. ambofaciens</i> possessed the rare ability to catalyze the N-acylation on the α-position of the lysine or of the amino-acid in N-terminal position of peptides. Two genes, <i>SAM23877_1485</i> and <i>SAM23877_1734</i>, were identified in the genome of <i>Streptomyces ambofaciens</i> ATCC23877 whose products show similarities with the previously identified aminoacylases from <i>Streptomyces mobaraensis</i>. The proteins encoded by these two genes were responsible for the major aminoacylase hydrolytic activities. Furthermore, we show that the hydrolysis of N-α-acetyl-L-lysine could be attributed to the product of <i>SAM23877_1734</i> gene.