Acylpeptides, the inhibitors of cyclic adenosine 3',5'-monophosphate phosphodiesterase. II. Amino acid sequence and location of lactone linkage.

Bacillus subtilis C-756 produced three kinds of inhibitors of cyclic adenosine 3',5'-monophosphate (cAMP) phosphodiesterase. Each was an acylpeptide consisting of a beta-hydroxy fatty acid residue and heptapeptide. By the application of mass spectrometry, the amino acid sequence of peptide was determined to be beta-hydroxy fatty acid-Glu-Leu-Leu-Val-Asp-Leu-Leu in all three cases. Each had a lactone linkage between the carboxyl group of C-terminal leucine and the beta-hydroxyl group of the fatty acid moiety. The total structures of these inhibitors were thus established.