Non disponible en dehors du Royaume-Uni et de l'Irlande

Application

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.

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, which is then isomerized to cholest-4-en-3-one with the release of H₂O₂.

Cholesterol Oxidase from microorganisms use cholesterol for carbon and energy. It is useful in diagnostic assays involving cholesterol, especially in lipid disorders. Cholesterol oxidase has an insecticidal property and aids protection against boll weevil larvae. The Streptomyces sp cholesterol oxidase has long shelf-life with good performance.

General description

Cholesterol Oxidase produced from Streptomyces sp corresponds to a molecular weight of 62 kDa. It has a pH and temperature optimum of 7 and 37 °C, respectively. Cholesterol Oxidase comprises a FAD-binding and a steroid-binding domain.

Packaging

100, 250 units in glass bottle

Physical form

lyophilized powder containing bovine serum albumin and sugars as stabilizers

Physical properties

Isoelectric point : 5.1 ± 0.1 and 5.4 ± 0.1Michaelis constant : 4.3 x 10‾⁵M(Cholesterol)Inhibitors : Ionic detergents, Hg⁺⁺, Ag⁺Optimum pH : 6.5 − 7.0 Optimum temperature : 45 – 50°CpH Stability : pH 5.0 – 10.0 (25°C, 20hr) Thermal stability : Below 45°C (pH 7.0, 15min)

Preparation Note

CHOD is soluble in cold 50 mM potassium phosphate buffer, pH 7.0. Prepare solutions immediately before use.

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.