Term coined by Paul Srere to refer to
complexes of metabolic enzymes. The classic example is the enzymes of the tricarboxylic acid cycle (
TCA) which makes reduced cofactors from citrate. Since this is part of the primary energy producing (and the
metabolic hub of) the cell, it is natural to assume it should be optimised to speed
reactions. The metabolon concept suggests that the enzymes of the cycle associate into a
supramolecular assembly, to provide a
microenvironment for the
substrate.
This would reduce the diffusion of substrate from the reacting enzymes and allow unstable intermediates to be transferred from one stage to the next. It has close links with the idea of substrate channelling, which can be equally fracticious. See quinary structure