Inhibition of rat diacylglycerol kinase activity by synthetic L-lysine containing polypeptides

We investigated whether or not synthetic polymers of amino acids affected the activity of rat diacylglycerol kinase. Among all the polypeptides of amino acids tested, only the polymers containing significant amounts of basic amino acid residues inhibited diacylglycerol kinase activity. Poly-L-lysine was a better inhibitor than poly-L-arginine. Both the density of positive charge and the nature of spacing amino acids of the inhibitory peptides were determining factors in interacting with the enzyme. Various polyamines were ineffective. Our observation indicated that the activity of diacylglycerol kinase might be controlled by a site which binds to a polycation.