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 ΔH# and the activation entropy ΔS# for BChE in starch and gelatin gels were evaluated. The values of ΔH# 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 ΔS# were 136 ± 12 and −2.03 ± 0.05 cal∙K−1∙mol−1, respectively. Likewise, the values of ΔH# for BChE in gelatin gel were 58 ± 6 and 109 ± 11 kcal/mol, and the values of ΔS# 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.

Enzymes Immobilized into Starch- and Gelatin-Based Hydrogels: Properties and Application in Inhibition Assay

“…For instance, 3% starch gel was chosen as a carrier for producing single-use BChE preparations [84]. It was also found that BChE activity was not affected by variations in potato starch concentration in the gel within a 1-4.2% range (Figure 4).…”

“…The rehydration of such preparations (soaking in buffer solution) took a long time, thus increasing the assay duration. For similar reasons, in experiments with BChE immobilization in gelatin gel, 1.4% of gelatin was chosen as the optimal percentage [58,84].…”

“…The rehydration of such preparations (soaking in buffer solution) took a long time, thus increasing the assay duration. For similar reasons, in experiments with BChE immobilization in gelatin gel, 1.4% of gelatin was chosen as the optimal percentage [58,84]. Table 1 lists values of immobilization yields of some enzymes immobilized by entrapment within the porous matrices of starch and gelatin.…”

“…Immobilization of Red + Luc in starch and gelatin gels widened the temperature range for maintaining the function of the immobilized enzymes (Table 2) [97]. The optimal temperatures for the enzymes immobilized in the starch and gelatin gels were 5-50 • C and 15-50 • C, respectively, while the free enzymes were completely inactivated at 40 • C. The starch and gelatin gels produced a stabilizing effect on BChE as well [84].…”

Water-Soluble Polymer Polyethylene Glycol: Effect on the Bioluminescent Reaction of the Marine Coelenterate Obelia and Coelenteramide-Containing Fluorescent Protein

“…It is known that water-soluble polymers can change the rates of cellular processes via stabilizing biological structures. It is shown [ 1 , 2 , 3 ] that enzymes included in the gelatin or starch gel matrix become more stable and lead to an increase in the activity. Moreover, water-soluble polymers such as polyethylene glycol (PEG) may cause toxic effects on living organisms [ 4 , 5 ].…”