Abstract: The effects of ethylene on α-amylase activity, kinetics and microenvironment were investigated. Compared with the control group, α-amylase activity was enhanced by ethylene at low concentration but inhibited at high concentration. However, ethylene hardly affected the optimum pH (6.0) for α-amylase, whereas it resulted in an increase in the optimum temperature by 5 ℃. The hydrolysis kinetics of α-amylase in the presence of low and high concentrations of ethylene followed a first-order kinetic equation (Michaelis-Menten), and the Lineweaver-Burk double-reciprocal curves were well fitted. The mechanism of action of ethylene in this respect was investigated. The ultraviolet (UV) absorption and fluorescence emission intensity of α-amylase were obviously enhanced with increasing ethylene concentration, and the absorption peak of α-amylase at 229 nm showed a red shift by 1 nm. After ethylene was added, the viscosity of α-amylase solution declined obviously compared with the control group, leading to a change in the microenvironment of α-amylase. This research is of great significance for supporting the safe application of ethylene in fruits and vegetables.

Key words: ethylene, effect, α-amylase, activity, microenvironment, kinetics