A thermostable soybean peroxidase-based biosensor was formed by cross-
linking and electrically ''wiring'' the enzyme through a redox-conduct
ing hydrogel to a glassy carbon electrode. At 65 degrees C the sensiti
vity of the sensor decayed only at a rate of only <2%/h. The sensor ma
intained, at 25 degrees C, the 1 A cm(-2) M(-1) sensitivity and the 0.
1-200 mu M dynamic range of the earlier ''wired'' horseradish peroxida
se-based sensors.