PROXIMATE REACTIONS. “Srere postulated that enzymes assembled into multimeric complexes to facilitate the vectorial flow of substrates and/or intermediates along a metabolic pathway. Enzyme organisation was predicted to decrease the diffusion time of substrates and/or intermediates between pathway steps, to stabilise transient intermediates and to minimise cross-reactions with competing pathways.”
http://onlinelibrary.wiley.com/doi/10.1111/febs.13744/full