Partial Characterization of Fatty Acid Synthase of Propionibacterium shermanii

Papanicolaou Cancer Research Institute, P.O. Box 016188, Miami, Florida 33101, U.S.A. ABSTRACT Fractionated extracts of Propionibacterium shermanii were found to contain the readily dissociable type of fatty acid synthase complex. For optimal activity the partially purified synthase required the presence of acetyl-CoA, malonyl-CoA, NADH and NADPH as well as a cell-free fraction containing the acyl carrier protein (ACP). When ACP-containing fractions obtained from P. shermanii grown in the presence of [1- 14 C]pantothenate were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis, the radioactivity was located in a peak corresponding to a molecular weight of approx. 8500-9000. The biological activity of the ACP was relatively heat-stable and trypsin-resistant. When the labelled ACP-containing fraction was subjected to gel filtration on a calibrated Sephadex G-75 column, a radioactive peak corresponding to a molecular weight of 22000 was obtained that could participate in the 14 CO 2 -malonyl-CoA exchange reaction in the presence of the other requisite components.