A kinetic approach to the thermal inactivation of an imobilized triosephosphate isomerase

The process of thermal inactivation of triosephosphate isomerase covalently attached to a silica‐based support activated with p ‐benzoquinone was found to be a complex one. At 50°C, a characteristic activation preceding the thermal inactivation was observed. Following the intramolecular changes caused by heat, the values of K M and V max were determined during the activation. It was presumed that the complex thermal inactivation kinetics reflects the microheterogeneity of the immobilized enzyme molecules. The phosphate ion proved to be a better stabilizer than the substrate. © 1992 John Wiley & Sons, Inc.