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

Thermokinetic behaviors of alpha-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 (K-m), apparent Michaelis constant (K '(m)), maximum velocity (V-max) and apparent maximum velocity (V'(max)) of the alpha-amylase catalyzed reaction were obtained, K-m-T and K-m-pH equation were deduced. According to K-m-T and K-m-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 alpha-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. (C) 2014 Published by Elsevier B.V.