Аннотация:The effect of phase transition of a thermosensitive matrix on temperature dependencies of observed activity, equilibrium, and kinetic constants of the enzymatic reaction was studied using (alpha) -chymotrypsin immobilized into thermosensitive poly-N-isopropylacrylamide gel as a model system. The behavior of the system is determined by the properties of the enzyme at temperatures less than critical temperature corresponding to phase transition of the polymeric gel but by the properties of the thermosensitive polymeric matrix at temperatures higher than that critical temperature. The phase transition of the thermosensitive gel was shown to affect weakly temperature dependencies of equilibrium parameters of enzymatic reactions. All reversible effects of the reduction of the enzymatic activity at high temperature are exclusively due to the changes in temperature behavior of kinetic parameters of the enzymatic reaction.