Activation by polyamines of the acetylation of endogenous histones in isolated chromatin and nuclei from Artemia.

Polyamines have been shown to increase the rate of transfer of acetyl groups from acetyl-CoA to endogenous histones in chromatin and nuclei from 50-h-old Artemia nauplii, with little changes in the rate of deacetylation. Polyamines were not acetylated by endogenous acetyltransferases in our assay conditions. The activation by polyamines showed a double specificity for both the effector, spermine, and the substrate, the histone H3. The same specificity was found for the activation of isolated histone acetyltransferase when assayed at subsaturating substrate concentration. The concentration of spermine required for half-maximal activation was found to be 50--60 microM.