[On the changes in alpha-chymotrypsin stability after its modification by polyelectrolytes].

Reversible thermal denaturation of alpha-chymotrypsin, its electrostatic complexes with carboxyl-containing polymers and the enzyme covalently bound with those polymers were studied. It was shown that the enzyme stability is affected by matrix, which manifests itself in a simultaneous decrease in enthalpy and enthropy of the reversible denaturation process and a simultaneous decrease in activation enthalpy and enthropy of denaturation. Modification and complexing of chymotrypsin with polymers has practically no effect on the activation parameters of renaturation. Differences in the original states of alpha-chymotrypsin and its derivatives and similarity of their activated states are proposed. The formation of ionic complexes of enzyme or covalent binding to polymers results in alteration of the protein native state similar to the denaturated state.