Catalytic activity of enzyme in water/organic cosolvent mixtures for the hydrolysis of p-nitrophenyl acetate and p-nitrophenyl benzoate
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چکیده
The dependence of the catalytic activities of α-chymotrypsin on the concentration of organic cosolvents (acetonitrile, dimethyl sulfoxide, dimethyl formamide, ethylene glycol, methanol, ethanol, propan-2-ol and tert-butanol) in mixed aqueous media has been studied towards hydrolysis of p-nitrophenyl acetate and p-nitrophenyl benzoate using cetyltriphenylphosphonium bromide surfactant at pH 7.75. The temperature dependence hydrolysis of PNPA and PNPB catalyzed by α-chymotrypsin has also been reported. Under all the conditions employed, the reaction follows a Michaelis-Menten mechanism. The organic solvent influences the kcat and KM. The effect of polarity of solvent on the catalytic activity has been discussed. It is observed that the catalytic efficiency of α-chymotrypsin is enhanced in aqueous-organic media. Possible mechanism of micellar enzymology and the effect of organic co-solvents have been discussed.
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