Spermidine/spermine N(1)-acetyltransferase (SSAT; EC 2.3.1.57) is a rate-limiting enzyme in the catabolic pathway of polyamine metabolism. It catalyzes the N(1)-acetylation of spermidine and spermine and, by the successive activity of polyamine oxidase, spermine can be converted to spermidine and spermidine to putrescine.
Zhu, Y.Q., Zhu, D.Y., Yin, L., Zhang, Y., Vonrhein, C., Wang, D.C. (2006) Crystal structure of human spermidine/spermine N1-acetyltransferase (hSSAT): the first structure of a new sequence family of transferase homologous superfamily Proteins 63: 1127-1131