THERMOSTABILIZED CHEMICAL DERIVATIVES OF HORSERADISH-PEROXIDASE

Horseradish peroxidase finds a variety of uses in analysis, immunology , organic synthesis, and biosensors. Although moderately stable, its a pplicability to biosensors and other fields would be greatly enhanced if it could be made yet more stable. Appropriate chemical modification can substantially stabilize enzymes. Here we describe the use of bis- imidates and of bis-succinimides to modify free amino groups of commer cial horseradish peroxidase under mild conditions of pH and temperatur e. Imidates yielded a marginal stabilization. Some of the succinimide derivatives, however are much more thermostable than the native enzyme . Apparent half-lives indicate stabilizations of 6- to 23-fold, depend ing on the bis-succinimide used. These modifications preserve the carb ohydrate side chains for subsequent reaction or immobilization.