Mechanism of metabolite transfer in coupled two-enzyme reactions involving aldolase

Transient-state kinetic experiments and analyses have been performed to examine the validity of hitherto unchallenged evidence proposed to be indicative of a channelled transfer of triose phosphates from aldolase to glyceraldehyde-3-phosphate dehydrogenase and glycerol-3-phosphate dehydrogenase. The results lend no support to such proposals, but show that the kinetic behaviour of the examined aldolase-dehydrogenase reactions is fully consistent with a free-diffusion mechanism of metabolite transfer.