Cholesterol Oxidase from Streptomyces sp. 25u

Cholesterol oxidase (CHOD) catalyzes the first step in cholesterol catabolism. Cholesterol oxidase from Streptomyces has been used in a study to assess the relationship between the micellar structure of model bile and the activity of esterase. Cholesterol oxidase from Streptomyces has also been used in a study to investigate the effects of sphingomyelin degradation on cell cholesterol oxidizability and steady-state distribution between the cell surface and the cell interior. This enzyme is useful for the determination of cholesterol in serum by coupling with cholesterol esterase. CHOD is used to determine serum cholesterol. It is the second most widely used enzyme in clinical applications after glucose oxidase. CHOD also finds application in the microanalysis of steroids in food samples and in distinguishing 3-ketosteroids from 3b-hydroxysteroids. Transgenic plants expressing cholesterol oxidase are being investigated in the fight against the cotton boll weevil. Cholesterol oxidase has also been used as a molecular probe to elucidate cellular membrane structures. Cholesterol oxidase (CHOD) is a monomeric flavoprotein containing FAD that catalyzes the first step in cholesterol catabolism. This bifunctional enzyme oxidizes cholesterol to cholest-5-en-3-one in an FAD-requiring step, which is then isomerized to cholest-4-en-3-one with the release of H₂O₂. One unit causes the formation of one µmole of hydrogen peroxide per minute at pH 7.0 and 37°C.