CARRIER-BOUND PROTEINS - PROPERTIES OF PEROXIDASE BOUND TO INSOLUBLE CARBOXYMETHYLCELLULOSE PARTICLES

Horse radish peroxidase has been chemically coupled to Carboxymethylcellulose in the presence of dicyclohexylcarbodiimide. The preparations with added hydrogen peroxide will oxidize phenols and aromatic amines. It was established that protein bound to cellulose can be quantitatively determined using the Lowry method. The activity of freeze-dried preparations of the bound enzyme can be restored by rehydration in water but suspensions of the bound enzyme retained only 18% of their original activity after exposure to room temperature for 167 hr. In the same period of time, solutions of free horse radish peroxidase retained 100% of their original activity. The relation between pH and activity using guaiacol as the substrate is similar to that of the free enzyme. The activation energy determined from k4 is approximately the same for both forms of the peroxidase: 6.5 kcal/mole for the free enzyme and 7.2 kcal/mole for the bound enzyme. The inhibition of enzymatic activity by fluoride and cyanide is about the same for both the free and bound horse radish peroxidase, but 10-3 m azide caused 82% inhibition of the free peroxidase and only 55% inhibition of the bound form. © 1969.