Chain elongation of fusaric acid and related compounds in rat liver.

Chain elongation of fusaric acid and related compounds in the presence of rat liver preparations was investigated by gas chromatography-mass spectrometry. The mitochondrial fraction catalyzed the elongation of the CoA esters of fusaric acid and 5-butyl-2-pyrimidinecarboxylic acid utilizing acetyl-CoA as a C2 donor. The microsomal fraction failed to afford elongation products. However, when the CoA ester of 3-(5-butyl-2-pyrimidinyl)-3-hydroxypropionic acid was incubated in the presence of the mitochondrial or the microsomal fraction, the corresponding alpha beta-unsaturated and saturated metabolites were identified in both cases, suggesting that the microsomal fraction could not catalyze the condensation or the keto-reduction of these heteroaromatic carboxylic acids.