Purification and partial characterization of a cholesterol oxidase from Streptomyces fradiae

An extracellular cholesterol oxidase from Streptomyces fradiae (PTCC 1121) was purified in one step using DEAE-Sepharose. The purified enzyme had a molecular weight of 60 KDa. The optimum pH and temperature for activity was found to be 7 and 70°C, respectively. This cholesterol oxidase was stable in pHs between 4–10 at 4°C until 4 h. Thermal stability experiments showed that it has high stability and retains its full activity at 50°C for 90 min. Km value for cholesterol oxidase was obtained to be about 7.06 × 10−5 Mol.