Enhancement of the activity of papain in mixed reverse micellar systems inthe presence of Tween80

An enhancement in the activity of papain (EC 3.4.22.2) was described in mix ed reverse micellar systems containing Tween80 compared with those without Tween80. By the use of these media, the hydrolytic and synthesis activities of papain were investigated in detail, respectively for the hydrolysis of N-alpha -benzoyl-L-arginine-p-nitroaniline (BNPNA) and the synthesis of the dipeptide Z-Gly-L-PheOMe (ZGPM). The reaction medium conditions (W-0, pH a nd Tween80 concentration) were optimized for both the hydrolytic and synthe sis reactions. The results showed a pronounced increase in the papain activ ity when a moderate amount of Tween80 was added into sodium di-2-ethylhexyl sulfosuccinate (AOT) or tetradecyltrimethylammonium bromide (TTAB) reverse micelles, either in the yield of dipeptide synthesis or in the initial rate of BNPNA hydrolysis. In addition, a mechanism to explain the enhancement o f enzymatic activity was proposed according to the change of the optimal pa rameters in the mixed and non-mixed reverse micellar systems, which is asso ciated with the environmental polarity surrounding the solubilised enzyme m olecules. (C) 2001 Society of Chemical Industry.