Properties of fatty acyl-CoA oxidase from rat liver, a peroxisomal flavoprotein

Fatty acyl-CoA oxidase from rat liver was partially purified and characterized as a peroxisomal flavoprotein oxidase. A sedimentation coefficient of 7.7 S was estimated from sucrose gradients and a Stokes radius of 42.3 Å was deduced from gel-exclusion chromatography. These data allow to estimate a molecular weight of 136,000 and a frictional ratio of 1.1. FAD, specifically required as a prosthetic group, is weakly bound. Still, FAD displays greater affinity for the free ap$\text{o}$ enzyme than for the putative apoenzyme-substrate complex formed with palmitoyl-CoA. In addition, it was established that the subcellular distribution of the fatty acyl-CoA oxidase, in complete liver homogenates fractionated in Metrizamide density gradients, parallels that of the peroxisomal marker catalase.