Pineal N -Acetyltransferase Is Inactivated by Disulfide-Containing Peptides: Insulin Is the Most Potent

Abstract
Pineal N-acetyltransferase can be inactivated in broken cell preparations by cystamine through a mechanism of thiol-disulfide exchange. Some, but not all, disulfide-containing peptides can inactivate this enzyme; the most potent inactivator is insulin. These findings suggest that a disulfide-containing peptide with high reactivity toward N-acetyltransferase may participate in the intracellular regulation of this enzyme.