The stability of enzymes is one of the bottleneck problems for its applications, andimprovement of enzyme stability is a hot topic in the enzyme engineering. A recombinantstrain (E.coli BL21(DE3)/pET28a-COD), expressed cholesterol oxidase (COD) intracellular,was constructed in the laboratory, however, the application of cholesterol oxidase was limiteddue to its poor stability. In the paper, affinity protocols were developed for the preparation ofpure cholesterol oxidase, enzyme inactivation mechanisms were ...