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The formation of enzyme-bound acetoacetate and its converstion to long chain fatty acids

1962; Elsevier BV; Volume: 7; Issue: 5 Linguagem: Inglês

10.1016/0006-291x(62)90326-1

1090-2104

Peter Goldman, P. Roy Vagelos,

Enzyme Catalysis and Immobilization

This chapter discusses acyl group transfer or acyl carrier protein (ACP). This protein was discovered as a heat-stable protein in extracts of Clostridium kluyveri where it was shown to function in the condensation reaction of fatty acid biosynthesis. ACP is involved as the acyl carrier in all the reactions of fatty acid biosynthesis, where it has a function analogous to that of CoA in the β oxidation of fatty acids. Acyl group transfers, involving ACP, are catalyzed by three enzymes of fatty acid synthesis, acetyl CoA–ACP transacylase, malonyl CoA–ACP transacylase, and β-ketoacyl ACP synthetase. Although the initial observations on the function of ACP were made with extracts of C. kluyveri, the decisive experiments that demonstrated the role of this protein in the synthesis of fatty acids followed the isolation of ACP from E. coli. In first of these experiments, a condensation–decarboxylation reaction was demonstrated that involved acetyl CoA, malonyl CoA, and substrate amounts of ACP. The products of this reaction were CO2, CoA, and acetoacetate bound through thioester linkage to ACP. The studies that have elucidated the structure and function of these three enzymes as well as of ACP are discussed this chapter.