Abstract: The power-time curves of a starch enzymatic catalyzed reaction were determined by using a 2277 thermal activity monitor (Sweden). According to thermokinetic theory and the reduced extent method, the values of Km and Vmax and the optimum acidity (pH=5.27)were obtained. Apparent K′m and Vmax data were gained for inhibiting (Li+, K+). The relationship between K′m　 and concentration of metal ions was established and so was the rule of the inhibitory affect of metal ions on an enzymatic catalyzed reaction.

Key words: induction , enzymatic catalyzed reaction, thermokinetics, microcalorimetry