THE BIOELECTROCHEMICAL RESPONSE OF THE POLYANILINE SARCOSINE OXIDASE ELECTRODE

Sarcosine oxidase has been immobilized in the polyaniline film by the electrochemical doping method. The response current of the polyaniline sarcosine electrode is a function of the applied potential, and incre ases with increasing pH in the region 7.0 to 8.75 and with increasing ionic strength of the buffer. The optimum pH of the immobilized sarcos ine oxidase is 8.75. The optimum temperature is 39.6 degrees C. The ac tivation energy of the enzyme-catalyzed reaction is 32.0 kJ mol(-1). T he apparent Michaelis-Menten constant K-m' is 1.7 mM. The enzyme elect rode has a high operational stability. The response current of the enz yme electrode increases linearly with increasing concentration of sarc osine in the range below 1.0 mM, and is not affected by formaldehyde a t concentrations less than 0.01 mM. Thus, the polyaniline sarcosine ox idase electrode can be used to determine sarcosine concentration.