Abstract
A trienzyme sensor for the detection of catechol and catecholamines is described on the basis of oxygen consumption measurement. Tyrosinase is combined with diaphorase to form a recycling system for the submicromolar concentration range. Glucose dehydrogenase as the third enzyme is used for internal NADH regeneration. With this probe the lower detection limit for catechol is 30 nmol/l. NADH and glucose concentrations were optimised for the measurement at 10mM. The pH profile is relatively sharp with an optimum pH of 5.25.