MURACEINS-MURAMYL PEPTIDES PRODUCED BY NOCARDIA ORIENTALIS AS ANGIOTENSIN-CONVERTING ENZYME INHIBITORS

I. TAXONOMY, FERMENTATION AND BIOLOGICAL PROPERTIES

Abstract

Three muraceins, a family of muramyl peptides, were isolated from Nocardia orientalis as inhibitors of angiotensin-converting enzyme (ACE). Muracein A, the most potent inhibitor, inhibited ACE competitively with a Ki of 1.5 μM. Liver alcohol dehydrogenase and carboxypeptidase A, two other zinc-containing enzymes, were not inhibited at 150 μM. Inhibition of ACE could not be reversed by divalent cations.