Mechanism of cholesterol side-chain cleavage. II. The enzymic hydroperoxide-glycol rearrangement of the epimeric 20-hydroperxycholesterols in 18O-enriched water.
Incubation of 20 alpha-hydroperoxycholesterol (I) and its 20 beta-isomer, 20 beta-hydroperoxy-20 isocholesterol (II) with adrenocortical mitochondrial preparations in the absence of molecular oxygen, in normal and 18O-enriched water, gave 20 alpha, 22R-dihydroxycholesterol (III) from I and 20 beta,21-dihydroxy-20-iso-cholesterol (IV) from II. Mass spectral analysis of the persilylated glycol products III and IV showed no uptake of 18O, indicating that the oxygen atoms of the C20-, C22- and C21-hydroxyl groups originated from the 20-hydroperoxy atomic oxygen complex is the intermediate in the enzymic oxidative reactions of cholesterol side-chain cleavage.
D000302:Adrenal Cortex / Q000378:metabolism*; D000311:Adrenal Glands / Q000378:metabolism*; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000378:metabolism; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism*; D013058:Mass Spectrometry; D008928:Mitochondria / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D010545:Peroxides / Q000378:metabolism; D013237:Stereoisomerism
D010545:Peroxides; D002784:Cholesterol; D010088:Oxidoreductases; D002786:Cholesterol Side-Chain Cleavage Enzyme