Patent attributes
Disclosed is an enzyme electrode comprising an electrode system comprising an insulating substrate having formed thereon a working electrode, a counter electrode and optionally a reference electrode, and a reaction layer formed on the electrode system, wherein the reaction layer comprises diaphorase (DI), 12α-hydroxysteroid dehydrogenase (12α-HSD) and nicotinamide adenine dinucleotide synthetase (NADS), at least a portion of the reaction layer being superposed on the working electrode, wherein the DI, 12α-HSD and NADS contained in the reaction layer are immobilized on the surface of the working electrode, so that a compound generated in the reaction layer can reach the surface of the working electrode. Also disclosed are a method for and a system for determining the concentration of adenosine triphosphate (ATP) in a sample by using the above-mentioned enzyme electrode.