Determination of dehydrogenase substrates by Clark-type oxygen electrodes and photosensitized coenzyme oxidation.

The photosensitized oxidation of NADPH by oxygen can be used for the determination of the reduced coenzymes by means of a Clark oxygen electrode. This method is suitable for coupling to enzyme-catalysed dehydrogenation reactions and thus for the determination of glucose-6-phosphate with glucose-6-phosphate dehydrogenase and of glucose with the combined ATP/hexokinase/glucose-6-phosphate dehydrogenase system, even with the use of immobilized mediators.