D-amino acid N-acetyltransferase of Saccharomyces cerevisiae: a close homologue of histone acetyltransferase Hpa2p acting exclusively on free D-amino acids.

D-Amino acid N-acetyltransferase is a unique enzyme of Saccharomyces cerevisiae acting specifically on D-amino acids. The enzyme was found to be encoded by HPA3, a putative histone/protein acetyl transferase gene, and we purified its gene product, Hpa3p, from recombinant Escherichia coli cells. Hpa3p shares 49% sequence identity and 81% sequence similarity with a histone acetyltransferase, Hpa2p, of S. cerevisiae. Hpa3p acts on a wide range of D-amino acids but shows extremely low activity toward histone. However, Hpa2p does not act on any of the free amino acids except L-lysine and D-lysine. Kinetic analyses suggest that Hpa3p catalyzes the N-acetylation of D-amino acids through an ordered bi-bi mechanism, in which acetyl-CoA is the first substrate to be bound and CoA is the last product to be liberated.