Description
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.
Abbr
CHOD, Native (Streptomyces sp.)
Applications
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. 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 3β-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.
Form
Lyophilized powder containing bovine serum albumin and sugars as stabilizers
Enzyme Commission Number
EC 1.1.3.6
Activity
> 20 units/mg protein
Molecular Weight
mol wt ~34 kDa
Isoelectric point
5.1 ± 0.1 and 5.4 ± 0.1
pH Stability
pH 5.0 – 10.0 (25°C, 20hr)
Michaelis Constant
4.3 x 10‾5M (Cholesterol)
Unit Definition
One unit will convert 1.0 μmole of cholesterol to 4-cholesten-3-one per min at pH 7.5 at 25°C. Note: 4-cholesten-3-one may undergo isomerization.
Optimum temperature
45 – 50°C
Thermal stability
Below 45°C (pH 7.0, 15min)
Buffer
50 mM potassium phosphate buffer, pH 7.0: soluble (Cold)
Inhibitors
Ionic detergents, Hg++, Ag+
Synonyms
EC 1.1.3.6, cholesterol-O2 oxidoreductase; 3β-hydroxy steroid oxidoreductase; 3β-hydroxysteroid:oxygen oxidoreductase; 9028-76-6
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