Acyl-CoA oxidase from Candida tropicalis

The preparation of a highly purified acyl-CoA oxidase from the cell extract of an n-alkane-utilizing yeast, Candida tropicalis, is described. It can be crystallized from ammonium sulfate solutions without an increase in specific activity, and is homogeneous on ultracentrifuge and disc electrophoresis. The enzyme is an octamer with approximately a 600,000 molecular weight, and has an isoelectric point of 5.5. It exhibits a typical flavoprotein spectrum with absorption maxima at 277, 365 and 445 nm, and contains 8 mol of FAD per mol of enzyme. The enzyme catalyzes the stoichiometric conversion of palmitoyl-CoA and O₂ into 2-hexadecenoyl-CoA and H₂O₂. It oxidizes acyl-CoAs with carbon chain lengths of 4 to 20, and is most active toward lauroyl-CoA, but acetyl- and succinyl-CoAs are not oxidized. The enzyme is sulfhydryl dependent and is inactivated by silver and mercury compounds.