Peroxisomal Degradation of Branched-Chain 2-Oxo Acids

Branched-chain 2-oxo acids which are formed by transamination of leucine, isoleucine, and valine are metabolized by the peroxisomes from mung bean (Vigna radiata L.) hypocotyls. Acylcoenzyme A (CoA) thio ester intermediates of the pathways were separated by reversed-phase high performance liquid chromatography. Retention time and cochromatography of individual acyl-CoA reference standards were used for identification of the acyl-CoA esters separated from the assay mixtures. Based on the results of identification and those of kinetic experiments, pathways of the peroxisomal degradation of 2-oxoisocaproate, 2-oxoisovalerate, and 2-oxo-3-methylvalerate are suggested.