Characterization of a novel spermidine/spermine acetyltransferase, BltD, from Bacillus subtilis

Overexpression of the BltD gene in Bacillus subtilis causes acetylation of the polyamines spermidine and spermine. BltD is co-regulated with another gene, Blt, which encodes a multidrug export protein whose overexpression facilitates spermidine export [Woolridge, Vazquez-Laslop, Markham, Chevalier, Gerner and Neyfakh (1997) J. Biol. Chem. 272, 8864-8866]. Here we show that BltD acetylates both spermidine and spermine at primary propyl amine moieties, with spermine being the preferred substrate. In the presence of saturating concentrations of acetyl CoA, BltD rapidly acetylates spermine at both the N1 and N12 positions. The Km (app) values for spermine, spermidine and N1-acetylspermine are