[Noncovalent complexes between alpha-chymotrypsin and block copolymers from ethylene and propylene oxides].

The ability of alpha-chymotrypsin to form complexes with amphiphilic block copolymer of ethylene oxide and propylene oxide upon heating up to 44-60 degrees C has been demonstrated for the first time. Depending on temperature and the initial component ratio, some complexes were obtained which varied in both composition and enzymatic activity. With a rise in the complexation temperature, the polymer content in the complex increased, while the enzymatic activity of the complex decreases. The complexes are very stable in water, but dissociate in 8 M urea and are characterized by enhanced thermal stability as compared with the original enzyme. It is assumed that both hydrophobic interactions and hydrogen bonds between the components are involved in the complex formation.