Deacetylation of N8-acetylspermidine by subcellular fractions of rat tissue

The in vitro deacetylation of N⁸-acetylspermidine by an enzyme activity in rat tissues is described. This deacetylase activity occurs as a soluble, cytoplasmic enzyme in rat liver and was detected in the 100,000g supernatant fraction of all tissues examined. The highest specific activity was found in liver. Spleen, kidney, and lung were found to contain 20–50% of the activity in liver, while heart, brain, and skeletal muscle exhibited from 2 to 10% of the activity in liver. Serum contained only barely detectable levels of activity, much lower than any of the tissues studied. The in vitro metabolism of N¹-acetylspermidine differed from that observed for N⁸-acetylspermidine and does not appear to involve a simple deacetylation reaction.