Collect. Czech. Chem. Commun. 1979, 44, 3090-3101

Reversible thermal denaturation of immobilized chymotrypsinogen

Eduard Brynda and Miroslav Bleha

Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6


The reversible thermal denaturation of chymotrypsinogen A bound to the insoluble poly(2-hydroxyethyl methacrylate) Spheron matrix was investigated by the fluorescence method. The applicability of fluorescence data in the calculation of the thermodynamic parameters of denaturation was tested. Equilibrium data were obtained for immobilized chymotrypsinogen and chymotrypsinogen in solution at various pH in the range 2-6. The binding to Spheron shifts the thermodynamic equlibrium in favour of the denaturated state. An increase in pH above 3 did not affect the denaturation of immobilized chymotrypsinogen. The denaturation is controlled by the first-order kinetics. The rate constants and magnitudes of changes of free energy, enthalpy and entropy were calculated for the transition from the native state into the activated state, and from denaturated state into the activated state. The temperature dependence of the rate constants for the denaturation of immobilized chymotrypsinogen is qualitatively different from for chymotrypsinogen in solution. The results were interpreted as effects of the physical interaction between the denaturated protein and polymeric matrix.