The Presence of a New 3‐Oxoacyl‐CoA Thiolase in Rat Liver Peroxisomes

Abstract

A novel 3‐oxoacyl‐CoA thiolase was found in rat liver. This thiolase, mitochondrial general 3‐oxoacyl‐CoA thiolase and acetoacetyl‐CoA thiolase were purified from the rat liver after the induction of these activities by the administration to rats of di(2‐ethylhexyl)phthalate, which enhanced the peroxisomal β‐oxidation activity. The new 3‐oxoacyl‐CoA thiolase was distinguished from mitochondrial and cytoplasmic thiolases by the following: DEAE‐cellulose chromatography, phosphocellulose chromatography, immunochemical titration, and substrate specificity. Subcellular fractionation of liver and sucrose‐density‐gradient centrifugation of the light mitochondrial fraction revealed that the new thiolase was mainly in peroxisomes.