Some biochemical properties of alkyl phosphotriesters of cyclic AMP

The biochemical properties of several alkyl phosphotriesters of cyclic AMP were studied with respect to their interactions with beef heart protein kinase and cyclic nucleotide phosphodiesterase. Ethyl and propyl triesters did not enhance the phosphorylation of histone by protein kinase and methyl, ethyl, propyl and butyl triesters were poor competitors for the cyclic AMP binding site of the enzyme. However, these alkyl phosphotriesters were effective inhibitors of cyclic nucleotide phosphodiesterase with the K i 's arrayed in the following order: methyl > ethyl > propyl > butyl > cetyl triester. Metabolic studies with mice indicated that intraperitoneal injection of low doses of propyl triester for one week significantly increased cyclic AMP concentration.