| 摘要 |
Cholesterol oxidase, useful as a diagnostic reagent for cholesterol in the bood, was prepd. by fermn. of Streptomyces sp. K-02. Thus Streptomyces sp. K-02 was cultivated in a medium contg. glucose 5, (NH4)2SO4 0.2, KCl 0.01, FeSO4 0.001, KH2PO4 0.2, MgSO4 0.02, and a yeast extract 2% to give a cholesterol oxidase at 30≦̸C for 18 hrs. For enzyme assay, 0.05ml of the enzyme prepn. were added to 3ml of the assay mixt. contg. 100mM phosphate buffer (pH7.0), 2.5ml; 10mM ortho-dianisidine, 0.1ml; and a peroxidase soln., 0.1ml. Absosrbance of the reaction rate per min. was measured at 460nm. One unit of cholesterol oxidase was defined as the enzyme amount that forms 1umole of H2O2 at 37≦̸C. 2-5 units of cholesterol oxidase/ml were obtd.
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