The primary intention when applying themoanalytical techniques to enzymatic reactions is the derivation of reliable thermochemical and thermokinetic information for selected reactions. The enzymatic oxidation of glucose was selected as a model reaction. Caloric measurements showed that the extrapolated thermal power at t = 0 is proportional to the concentration of the substrate in GOD-catalysed glucose oxidation, so that measurement can be restricted to the determination of the initial power. The range of measurable glucose oxidation was initially limited by the oxygen content of the solution (0-1.4 mmol l-1). This concentration range has been expanded considerably by adding mediators. The additional use of mutarotase resulted in an increased reaction rate.