Thermobarostability of α-chymotrypsin in reversed micelles of aerosol OT in octane solvated by water-glycerol mixtures

Thermostability of α‐chymotrypsin at normal pressure in reversed micelles depends on both an effective surfactant solvation degree and glycerol content in the system. The difference in α‐chymotrypsin stability in reversed micelles at various glycerol concentrations [up to 60% (v/v)] was more pronounced at high surfactant degrees of solvation, R ⩾ 16. After a 1‐h incubation at 40°C in “aqueous” reversed micelles (in the absence of glycerol), α‐chymotrypsin retained only 1% of initial catalytic activity and 10, 22, 59, and 48% residual activity in glycerol‐solvated micelles with 20, 30, 50, and 60% (v/v) glycerol, respectively. The explanation of the observed effects is given in the frames of micellar matrix structural order increasing in the presence of glycerol as a water‐miscible cosolvent that leads to the decreasing mobility of the α‐chymotrypsin molecule and, thus the increase of its stability. It was found that glycerol or hydrostatic pressure could be used to stabilize α‐chymotrypsin in reversed micelles; a lower pressure is necessary to reach a given level of enzyme stability in the presence of glycerol. ©1998 John Wiley & Sons, Inc. Biotechnol Bioeng 57: 552‐556, 1998.