Noninvolvement of Acyl Carrier Protein with Citrate Synthase and Malate Synthase

Stuart L. Marcus, Henry C. Reeves, Samuel J. Ajl
1968 Journal of Bacteriology  
Acyl carrier protein (ACP coli) was isolated from commercially grown Escherichia coli B and was acetylated by chemical methods. Biological activity of the synthesized acetyl-ACP coli was checked in an in vitro fatty acid-synthesizing system isolated from E. coli B. Since acetyl-ACP is preferred over acetyl-coenzyme A (CoA) as a substrate in these reactions, the possibility that it may substitute for acetyl-CoA in biosynthetically and oxidatively important cellular pathways (glyoxylate and Krebs
more » ... cycles, respectively) was examined. Acetyl-ACP was tested for substrate activity with the enzyme of each cycle which has been found to utilize acetyl-CoA. Crystalline citrate synthase (EC of porcine origin (Calbiochem) was found to be inactive with acetyl-ACP coil, which acted neither as a substrate nor as an inhibitor in the presence of acetyl-CoA. Malate synthase (EC of the acetate type was isolated from acetate-grown cells of a mutant of E. coli K-12 (VGD3H5) and was also found to be inactive with acetyl-ACP coli. The significance of these results and of the recent discovery of another phosphopantetheine-containing protein are discussed.
doi:10.1128/jb.96.4.1281-1284.1968 fatcat:pwosedphhndvfa4wshejlrbzhe