Inactivation of enzymes under high pressure : 1. Inactivation of salivary α-amylase under high pressure

Abstract

It has been found that α-amylase of human saliva is inactivated in aqueous solution by an application of high pressure above 5, 000kg/cm^2. The inactivation by high pressure follows first order kinetics, with respect to the enzyme concentration. The rate of inactivation is strongly accelerated by an increase in pressure corresponding -32 cm^3/mole of the activation volume at 30°. The activation enthalpy and the activation entropy are 8.2kcal./mole and -44 e. u. respectively, at 7500kg/cm^2 and pH 6.9. The rate of inactivation by pressure is also roughly proportional to hydrogen ion concentration in the solution at a pH between 4 and 10. These features of the inactivation by pressure of salivary α-amylase, resemble closely those of bacterial α-amylase.