[Covalent binding of peroxidase to CH- and AH-Sepharose 4 B]

The properties of peroxidase insolubilized by covalent binding to CH- and AH-Sepharose 4 B in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) are described. CH-Sepharose 4 B bound peroxidase yields an enzyme preparation with a residual specific activity of 60.6%. When bound to AH-Sepharose 4 B, the residual specific activity is to 78%. The reasons of these differences in the catalytic activity of the two insolubilized enzyme preparations are discussed. By covalent binding on CH- and AH-Sepharose 4 B, peroxidase exibits no changes in its pH optimum; it virtually keeps the same activity after being used ten times. Insolubilized peroxidase preparations, dried and reimbibed after being stored for 6 weeks at room temperature still display 50% of the initial specific activity of the insolubilized enzyme. Stored in acetate buffer, the enzyme preparations maintain their activity during all this interval.