Mucor circinelloides F6-3-12 tannase was conjugated to several activated polysaccharides and polyethylene glycol (PEG). The enzyme conjugates were evaluated for the kinetic and thermodynamic stability. The conjugated enzyme with PEG had the highest thermal stability (T1/2 at 50°C = 704.54 min). Compared to the native tannase, the PEG-conjugated preparation exhibited lower activation energy (Ea ), lower deactivation constant rate (kd), higher t1/2 and D values (decimal reduction time) within the temperature range of 40–60°C. The values thermodynamic parameters entropy (ΔS*) and enthalpy (ΔH*) for irreversible thermal inactivation of the enzyme was significantly decreased upon conjugation with PEG. Further, the calculated value of deactivation energy for irreversible thermal inactivation (Ead) for PEG-conjugated tannase was 102 KJ mole-1 higher over the native one. The results of thermodynamic analysis for tannic acid hydrolysis indicated that the enthalpy of activation (ΔH*) and free energy of activation (free energy of substrate binding) ΔG*E–S and (ΔG*), (free energy of transition state) ΔG*E–T values were lower for the conjugated tannase. Similarly, there was significant improvement of kcat, kcat/Km values. Further, the calculated value of activation energy for thermal denaturation (Ead) for PEG- conjugated tannase was 102 KJ mole-1 higher over the native one. The results of thermodynamic analysis for tannic acid hydrolysis indicated that the enthalpy of activation (ΔH*) and free energy of activation (free energy of substrate binding) ΔG*E–S and (ΔG*), (free energy of transition state) ΔG*E–T values were lower for the conjugated tannase. Similarly, there was significant improvement of kcat, kcat/Km values.
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