Fatty acid synthetase from Brevibacterium ammoniagenes: formation of monounsaturated fatty acids by a multienzyme complex.

A multienzyme fatty acid synthetase complex isolated from Brevibacterium ammoniagenes has been purified to a specific activity of 1440 nmol of malonyl-CoA incorporated per min/mg. The enzyme is homogeneous, as judged by gel electrophoresis on agarose gels, and has a molecular weight of 1.2 X 10(6). Both NADPH and NADH are required for activity. In contrast to other fatty acid synthetase complexes, the enzyme catalyzes the synthesis of both long-chain saturated and monounsaturated fatty acids from malonyl-CoA and acetyl-CoA. The formation of unsaturated fatty acids is oxygen-independent and sharply reduced by 3-decynoyl-N-acetylcysteamine, a known inhibitor of Escherchia coli beta-hydroxydecanoyl thioester dehydrase (EC 4.2.1.60).