Kinetic study of α-amylase in the process of starch hydrolysis by microcalorimetry

Thermokinetic behaviors of α-amylase in the process of starch hydrolysis were studied under the conditions of different temperatures, different pH and metal ions by using thermokinetics theory and reduced extent method; the Michaelis constant (Km), apparent Michaelis constant (K′m), maximum velocity (Vmax) and apparent maximum velocity (V′max) of the α-amylase catalyzed reaction were obtained, Km-T and Km-pH equation were deduced. According to Km-T and Km-pH equation, the optimum temperature is 315.04 K and the optimum acidity is pH = 5.08. At the conditions of T = 313.15 K and pH = 5.02, the influence of metal ions (Ag+, Cu2+ and Zn2+) in α-amylase catalyzed reaction were studied; according to the data, it was discovered that the inhibitory type were versa-competitive inhibition and inhibitory consecution were Ag+ > Cu2+ > Zn2+ at the same concentration.