[Interaction of alpha-chymotrypsin with dimethylsulfoxide: a change of substrate could change the mechanism of interaction]. / Vzaimodeistvie alpha-khimotripsina s dimetilsul'foksidom: smeni substrat--"izmenish'" mekhanizm vzaimodeistvii.

ABSTRACT

The kinetic behavior of alpha-chymotrypsin was studied in water-DMSO mixtures at concentrations of the organic solvent that do not cause irreversible denaturation of the enzyme. Various substrates (N-substituted derivatives of L-tyrosine) were found to display substantially different kinetic patterns of interaction with alpha-chymotrypsin, which can be described by totally different kinetic schemes. The differences were ascribed to competition between the N-acyl group of the substrate and the DMSO molecule at the S2-site of substrate binding to the active site of the enzyme.