Discovery, purification and characterization of the angiotensin converting enzyme inhibitor, L-681,176, produced by Streptomyces sp. MA 5143a.

Abstract

L-681, 176, an inhibitor of angiotensin converting enzyme was found in the culture filtrate of Streptomyces sp. MA 5143. The I50 of the crystalline inhibitor is about 1.3μg/ml and the inhibition is reversed by zinc sulfate. In rats, L-681, 176 exhibits a dose-related inhibition of the pressor response to angiotensin I with an ID50 of 142 mg/kg when administered intravenously. The structure of L-681, 176 is similar to that of marasmine but lacking one carboxyl group. The maximum yield of L-681, 176 occurs after three to four days growth at 28°C.