High-pressure stabilization of α-chymotrypsin entrapped in reversed micelles of aerosol OT in octane against thermal inactivation

α-Chymotrypsin (CT) solubilized in reversed micelles of sodium bis-(2-ethylhexyl)-sulfosuccinate (AOT) undergoes thermal inactivation and the enzyme stability decreases significantly when temperature increases (25–40°C). The half-life of CT in micelles shows a bell-shaped dependence on the degree of hydration of AOT ( w 0) analogous to the previously obtained dependence on w 0 for the enzyme activity. The optima of catalytic activity and thermal stability have been observed under conditions where the diameter of the inner aqueous cavity of the micelle is close to the size of the enzyme molecule ( w 0 = 10). Application of high hydrostatic pressure in the range of 1–1500 atm (bar) stabilizes CT against thermal inactivation at all hydration degrees ( w 0) from 7 to 20; the stabilization effect is most pronounced under the experimental conditions being far from the optimum for catalytic activity.