Heat measurements applied to biochemical analysis: Glucose in human serum

Abstract

Microcalorimetric measurement of enthalpy change for the hexokinase catalyzed reaction of ATP with glucose (inTRIS/HCl buffer containing MgCl 2) was carried out with glucose concentrations from zero to 1350 mg · liter −1. A linear relationship between measured heat and glucose concentration was found, from which the reaction enthalpy was calculated to be −61.4 kJ·mole −1. This linear relation, combined with calorimetric measurements of the same process carried out with 0.15 ml samples of human serum, was used to calculate glucose concentrations in the serum. For 45 samples containing glucose levels ranging from 420 to about 4000 mg · liter −1 the results show only slight systematic differents from measurements made by the glucose oxidase procedure of Gochman and Schmitz.