PURIFICATION AND CHARACTERIZATION OF SULOCHRIN OXIDASE FROM PENICILLIUM FREQUENTANS

Sulochrin oxidase, an enzyme catalyzing regio- and stereospecific phen ol oxidative coupling reaction to form (+)-bisdechlorogeodin from sulo chrin, was isolated from Penicillium frequentans CMI 96659. By chromat ographies on DEAE-cellulose, hydroxyapatite, Phenyl-Sepharose, Mono P, Mono Q, and HPLC gel filtration columns, sulochrin oxidase was purifi ed to apparent homogeneity. The purified enzyme had a molecular weight of 230 K as estimated by gel filtration and 110 K as estimated by sod ium dodecylsulfate-polyacrylamide gel electrophoresis under denaturing conditions, suggesting that the active enzyme was a homodimer. The en zyme showed pI 4.0 and an optimum pH of 6. The enzyme activity was str ongly inhibited by the copper-chelating reagent, diethyldithiocarbamat e, and did not recover its full activity even after removing the inhib itor by dialysis. However, enzyme activity was fully restored by the a ddition of Cu2+. Thus, sulochrin oxidase is considered to be a copper protein. The enzyme showed high substrate specificity for benzophenone compounds such as sulochrin and dihydrogeodin.