Biosynthesis of CoA from pantothenic acid

Figure 1 Biosynthesis of CoA from pantothenic acid. El pantothenate kinase (CoaA) E2 phosphopantothenoylcysteine synthetase (CoaB) ...

The biosynthesis of CoA from pantothenic acid was markedly increased in liver supernatant after admini-stration of clofibrate. Both by estimating the final product directly, or by the incorporation of pantothenic acid into CoA, rates about 3 fold of normal were found (table 3)-... 

Table 3. Increased biosynthesis of CoA from pantothenic acid in livers from clofibrate-treated rats...

Biosynthesis of CoA from pantothenic acid in the supernatant fraction of the liver. All enzymes required for the biosynthesis of CoA from pantothenic acid have been isolated from the soluble fraction of the cell (8). By using the vitro system of Abiko (cf. 8) for the synthesis of CoA from pantothenic acid, we found the capacity for CoA-biosynthesis to be markedly increased after treatment with clofibrate (2). Dephospho-CoA kinase was not significantly (or only very slightly) increased, but the activity of pantothenate kinase was more than doubled. CoA will exert feed-back inhibition of pantothenate kinase (8), and the extent of this inhibition was not changed by clofibrate (2). 

CoA plays an important role in various metabolic reactions. This compound is used widely in biochemistry, and its usefulness in medicine and in analytical fields has been discussed. The recent discovery of an acyl carrier protein containing an intermediate of CoA biosynthesis, P-pantetheine, as a prosthetic group, has emphasized the significance of CoA and its derivatives in biochemistry. The biosynthesis of this coenz3mie from pantothenic acid, cysteine and ATP requires five sequential enz3miatic steps as follows (3)5... 

The biosynthesis of CoA in animals requires five enzymes. The first three are foimd only in the cytosol, and the other two are also found in mitochondria. Reaction IV is reversible. Four moles of ATP are required for the biosynthesis of one mole CoA from one mole of pantothenic acid. Two additional enzymes... 

Biosynthesis of coen2yme A (CoA) ia mammalian cells incorporates pantothenic acid. Coen2yme A, an acyl group carrier, is a cofactor for various en2ymatic reactions and serves as either a hydrogen donor or an acceptor. Pantothenic acid is also a stmctural component of acyl carrier protein (AGP). AGP is an essential component of the fatty acid synthetase complex, and is therefore requited for fatty acid synthesis. Free pantothenic acid is isolated from hver, and is a pale yeUow, viscous, and hygroscopic oil. 

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