FRUCTOSE-GLUCOSE ENZYMATIC ISOMERIZATION

In this piece of work we present the results obtained from the kinetic study of the fructose-glucose isomerization using the enzyme D-xylose -ketol-isomerase in soluble form at pH 7.5. The temperature has been v aried within the 40 to 60-degree-C range, as has the total hexose conc entration between 0.5 and 2.0 M. The analysis carried out on the influ ence of the enzyme concentration shows that the conversion reached dep ends on the C(E).t intensive factor (enzyme concentration . reaction t ime). The fructose-glucose enzymatic isomerization is a reversible rea ction which goes through the following mechanism: [GRAPHICS] This mech anism leads to the following kinetic expression in terms of the conver sion, x [GRAPHICS] On applying this expression to kinetic experiments, it has been observed that K(b) almost-equal-to 0, which would imply t hat the isomerization reaction is in fitting with pseudo first-order k inetics, meaning that the Michaelis-Menten constants are practically t he same in both directions and, thus, that the affinity of both isomer s by the enzyme is very close. We have determined the elementary kinet ic constants of the isomerization reaction, the following equations be ing obtained in terms of temperature [GRAPHICS]