Enzymes hydrolytic catalytic activity toward

Table I. Hydrolytic catalytic activity, Kd (sec ), of selected enzymes toward some nerve agents...

Although polyethyleneimine possesses moderate catalytic effects on several hydrolysis reactions, the polymer modified with long allQrl chains show mudi enhanced reactivity toward hydrophobic substrates. Remaikable catalytic effects were observed in the hydrolysis of phenyl esters and a sulfate ester catalyzed by the methylene-imidazole-modified polymer. These results were explained as arising from the hi y brandied, compact stmcture of the polyediyleneimine derivative. Klotz called the imidazole-containing polyethyleneimine synzyme (synthetic enzyme), on the basis of its stmctural characteristics and catalytic activity which are comparable to hydrolytic enzymes. 

In the following years some more studies appeared in the literature concerning trypsin activity in reverse micelles in relation to various characteristics of the reaction medium. Fadnavis et al. studied the pH dependence of hydrolytic activity of trypsin in CTAB reverse micelles toward a positively charged model ester substrate [74]. It was found that enzyme activity variations as a function of w are pH dependent. In 2005, Dasgupta and coworkers related the catalytic activity of trypsin in reverse micelles formulated with cationic surfactants with the concentration of the water-pool components and the aggregate size to delineate the independent role of both parameters [75]. Finally, in 2006, the influence of ethylene glycol on the thermostability of trypsin in AOT reverse micelles was examined and was found to exhibit a positive effect [76]. 

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