Application
Cholesterol oxidase is used to determine serum cholesterol. The enzyme 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. CHOD has also been used as a molecular probe to elucidate cellular membrane structures.
Biochem/physiol Actions
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. This is subsequently isomerized to cholest-4-en-3-one with the release of H2O2. Optimum pH of the enzyme is 7.0. Hg2+, Ag+, ionic detergents inhibit the enzyme activity.
Preparation Note
Dissolves in cold 50 mM potassium phosphate buffer, pH 7.0. Solution is to be prepared just before use.
Other Notes
One unit will convert 1.0 μmol of cholesterol to 4-cholesten-3-one per minute at 37 °C and pH 7.0 in a peroxidase linked system.
| Quality Segment | 200 |
| form | lyophilized powder |
| specific activity | ≥10 units/mg protein |
| mol wt | 55 kDa |
| solubility | 50 mM potassium phosphate buffer, pH 7.0: soluble |
| storage temp. | −20°C |
