IMMOBILIZATION OF 2 ENZYME-SYSTEM OF GLUC OAMYLASE AND GLUCOSEOXIDASEONTO PLATINUM-ELECTRODE AND ITS CHARACTERISTICS AS MALTOSE SENSOR

Amino groups were attached to a platinized platinum electrode through alkylamine-silanization. Glucoamylase (GA) and glucoseoxidase (GOD) we re then immobilized directly onto the platinum electrode. The immobili zed two enzyme electrode (GA-GOD-Pt) was coupled with a Ag/AgCl electr ode as its counter electrode and its characteristics as a maltose sens or were investigated. An increased linearity was observed as the pH va lue of the ambient solution increased. Its tendency of increased linea rity with increased pH value toward 7.5 was examined through the aid o f theoretical analysis of the relation between electrode current and m altose concentration and the use of the GA-GOD-Pt electrode under cond itions of somewhat depressed GA activity was recommended. The dynamic response of the GA-GOD-Pt to the stepwise change of maltose concentrat ion was found to be expressed by a first order response model without time delay.