The occurrence, subcellular localization and partial purification of diamine acetyltransferase in the yeast Candida boidinii grown on spermidine or putrescine as sole nitrogen source.

The yeast Candida boidinii when grown on spermidine, diaminopropane, putrescine or cadaverine as sole nitrogen source contains an N-acetyltransferase capable of acetylating the primary amino groups of spermine, spermidine, acetylspermidines, acetylputrescine and alpha, omega-diaminoalkanes. In the case of spermidine, the products were N1-acetylspermidine and N8-acetylspermidine in the ratio 50:45 with traces of other unidentified products. The enzyme was partially purified and the stoichiometry determined, together with apparent Km and V values for a number of substrates. The pH optimum was about 8.8 for putrescine and 9.3 for spermidine. The unstable enzyme was partially stabilized by 10% (v/v) glycerol or bovine serum albumin (5 mg/ml). The kinetic parameters were determined with putrescine as substrate and the mechanism shown to be of the sequential type. The enzyme was shown to be located in the mitochondria of C. boidinii, in contrast to mammalian N-acetyltransferases. The enzyme was found in a number of other yeast species when grown on spermidine or putrescine, but was only present in those species that had previously been found to contain polyamine oxidase. It is suggested that in C. boidinii, as in mammals, acetylation of spermidine and putrescine must precede their catabolism.