Thermal inactivation of butyrylcholinesterase in starch and gelatin gels

Abstract

The present study demonstrates a simple approach to enhancing thermal stability of butyrylcholinesterase (BChE) by using natural polymers. Analysis of thermal inactivation of the tetrameric BChE in starch and gelatin gels at 50–64◦C showed that thermal inactivation followed second-order kinetics and involved two alternating processes of BChE inactivation, which occurred at different rates (fast and slow processes). The activation enthalpy ∆H# and the activation entropy ∆S# for BChE in starch and gelatin gels were evaluated. The values of ∆H# for the fast and the slow thermal inactivation of BChE in starch gel were 61 ± 3, and 22 ± 2 kcal/mol, respectively, and the values of ∆S# were 136 ± 12 and −2.03 ± 0.05 cal·K−1·mol−1, respectively. Likewise, the values of ∆H# for BChE in gelatin gel were 58 ± 6 and 109 ± 11 kcal/mol, and the values of ∆S# were 149 ± 16 and 262 ± 21 cal·K−1·mol−1, respectively. The values of the activation parameters obtained in this study suggest that starch gel produced a stronger stabilizing effect on BChE exposed to elevated temperatures over long periods compared with gelatin gel.