Surface, conformational and catalytic activity approach of α-chymotrypsin and trypsin in micellar media

Abstract

The surface tension measurements have carried out to study the interactions among cetyltriphenylphosphonium bromide (CTPB) with α-chymotrypsin (α-CT) and trypsin in aqueous medium at pH 7.75. The surface parameter i.e. critical micelle concentrations (CMCs), the maximum surface excess at air/water interface (Γmax), minimum area per surfactant molecule (Amin) and the surface pressure at CMC (πcmc) have been evaluated using conductivity and surface tension measurement. Thermodynamic parameters indicate that enzyme-CTPB monomeric aggregation started to form micelles at a higher concentration of surfactant to compare with the CMC of pure CTPB micelles. Fluorescence measurement outlined the complex formation between α-CT and CTPB, which explains that the hydrophobic part of the surfactant play important role for enzyme conformation and folding. Comparative study of hydrolysis of p-nitrophenyl acetate (PNPA) and p-nitrophenyl benzoate (PNPB) catalyzed by trypsin in the presence of CTPB, CTAB and SB3-12 surfactants has also been investigated and explain in detail.