ON THE ROLE OF ENZYME-KINETIC PARAMETERS IN DETERMINING THE EFFECTIVENESS WITH WHICH CHANNELING CAN DECREASE THE SIZE OF A METABOLITE POOL

Recently, it has been argued that the phenomenon of direct transfer of intermediate metabolites between adjacent enzymes, also known as meta bolic channelling, would not decrease the concentration of those inter mediates in the 'bulk' solution. However, this conclusion has been dra wn by extrapolation from the results of simulations with a rather rest ricted set of parameters. We show that, for a number of kinetic cases, the existence of metabolic channelling can decrease the size of the s oluble pool of intermediates. When the enzyme(s) 'downstream' of the c hannel have a catalytic capacity that is large relative to the enzymes 'upstream' of the channel, the decrease of concentration can be subst antial (3 orders of magnitude).