Acetyl-CoA-dependent elongation of fatty acids in Mycobacterium smegmatis.
An enzyme system of Mycobacterium smegmatis catalyzing the elongation of medium-chain fatty acids with acetyl-CoA was obtained free from de novo fatty acid synthetase by ammonium sulfate fractionation. The system was resolved by gel filtration and DEAE-cellulose chromatography into three fractions, all of which were required for reconstitution of the elongation activity. The three fractions were highly purified enoyl-CoA hydratase, highly purified 3-hydroxyacyl-CoA dehydrogenase, and a fraction containing both enoyl-CoA reductase and thiolase. The reconstituted system was avidin-insenstive, required NADH as a sole hydrogen donor, and was sensitive to pCMB, but not to N-ethylmaleimide or monoiodoacetate. Decanoyl-CoA and octanoyl-CoA were the best primers for the elongation system. When decanoyl-CoA was used as the primer, the major product was found to be a lauroyl derivative (probably lauroyl-CoA). Evidence was obtained suggesting that acyl-CoA dehydrogenase, catalyzing the first step of beta-oxidation, was not functional in the elongation system.
D000101:Acetyl-CoA C-Acetyltransferase / Q000378:metabolism*; D000123:Acetyltransferases / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D004746:Enoyl-CoA Hydratase / Q000302:isolation & purification / Q000378:metabolism*; D006836:Hydro-Lyases / Q000378:metabolism*; D009161:Mycobacterium / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D013439:Sulfhydryl Reagents; D009243:NAD; D000123:Acetyltransferases; D000101:Acetyl-CoA C-Acetyltransferase; D006836:Hydro-Lyases; D004746:Enoyl-CoA Hydratase