Amperometric ATP Biosensors Based on Coimmobilizations of p-Hydroxybenzoate Hydroxylase, Glucose-6-Phosphate Dehydrogenase, and Hexokinase on Clark-Type and Screen-Printed Electrodes

Two types of amperometric trienzyme ATP biosensors were developed based on new combinations of enzymes and electrodes by using the coimmobilizations of p-hydroxybenzoate hydroxylase (HBH), glucose-6-phosphate dehydrogenase (G6PDH), and hexokinase (HEX) on a Clark-type oxygen electrode and on a screen-printed electrode. The principles of the determinations are as follows: HEX transfers the phosphate group from ATP to glucose to form glucose-6-phosphate. G6PDH catalyzes the specific dehydrogenation of glucose-6-phosphate by consuming NADP$^{+}$. The product, NADPH initiates the irreversible hydroxylation of p-hydroxybenzoate by HBH to consume dissolved oxygen which results in a detectable signal on a Clark-type electrode and generate 3, 4-dihydroxybenzoate which results in a detectable signal on a screen-printed electrode. Both sensors show high-performance characteristics with broad detection ranges, short measuring times and good specificities.