Kinetics and thermodynamics of the native and mutated extracellular endo-glucanases from Cellulomonas biazotea.

The mutation had dramatic effect on the kinetic and thermodynamic parameters inferring thermostability of endo-glucanase from Cellulomonas biazotea mutant 51 SM(r). The denaturation activation energies of native and mutated enzymes were 73.3 and 68.8 kJ/mol respectively. They showed compensation effect at 55 degrees C. Both enthalpy and entropy values of irreversible thermal inactivation for mutated enzyme were decreased suggesting that the mutation partly stabilized the enzyme.