[Comparison of the activities of free and carrier fixed horseradish peroxidase]

Commerical horseradish-peroxidase was covalently bound to BrCN-activated sepharose. The activity parameters Vmax and Km were determined by the leukomalachite green reaction. Compared with the soluble enzyme, the immobilized POD has a relative residual activity of 22%. Dimethylsulfoxide and formamide were found to diminish the enzymatic activity in a concentration-dependent manner. The activity of the free enzyme in aqueous formamide solution (10%) is reduced by 43%, that of the insolubilized enzyme by 68%. Dimethylsulfoxide (15%) does not alter the LMG conversion rate of free POD, whilst a rate loss by 60% was observed for the immobilized enzyme.