Cholesterol oxidase and method of extracting from nocardia

摘要

Enzyme preparations which will convert cholesterol to DELTA 4-cholestenone and hydrogen peroxide are obtained from certain Nocardia species belonging to the Mycobacterium rhodocrous group. The preparations have a cholesterol oxidase specific activity of at least 1 unit per 5 mg of protein nitrogen and, when in liquid form, a potency of at least 10-2 units/ml. They are prepared by growing the organism and recovering the enzyme preparation, preferably by extracting the harvested cells with a surface active agent such as Triton X-100. The enzyme preparations are used to assay for cholesterol by measuring the amount in which one of the products of the cholesterol oxidase reaction, preferably hydrogen peroxide, is formed or the quantity in which oxygen is used.