PERIOD-DOUBLING BIFURCATIONS AND CHAOS IN AN ENZYME REACTION

The peroxidase-oxidase (PO) reaction is the peroxidase-catalyzed oxidation of organic electron donors with molecular oxygen as the oxidant. With NADH as the electron donor, the PO reaction is one of the simplest biochemical reactions showing nonlinear behavior such as bistability and oscillations. A few experimental observations have also indicated chaotic dynamics in this reaction. However, until now the evidence for chaos has been inconclusive, partially because no route to chaos has been established experimentally. Here we present the first experimental observation of period doubling bifurcations leading to chaos in the PO reaction.