Electron Transfer Kinetics between PQQ-dependent Soluble Glucose Dehydrogenase and Mediators

Abstract

Steady-state kinetic parameters between PQQ-dependent soluble glucose dehydrogenase (PQQ-sGDH) and mediators were evaluated based on a theory of bioelectrocatalysis. Quinones showed bi-molecular reaction constants in the order of 1010 M−1 s−1 as the limiting values, while the values of Os-complexes were two or three orders smaller. The magnitude of the limiting values was interpreted in terms of the long-range electron transfer in the active center as well as the diffusion-controlled reaction model.