An aminoacylase activity from catalyzes the acylation of lysine on α-position and peptides on N-terminal position.

The presence of aminoacylase activities was investigated in a crude extract of 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 (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 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, and , were identified in the genome of ATCC23877 whose products show similarities with the previously identified aminoacylases from . 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 gene.