A new view of cellular metabolism starts to emerge, emphasizing the contribution of organization of catalytic structures upon intracellular surfaces (membranes and cytoskeleton), and the differences between heterogeneous and homogeneous (as in ideal solution) catalytic behavior. Thus, the dynamic association and/or segregation of enzymes (even in the cytosol) is believed to mediate channeling of reactants in the desired direction and/or pathway, according to metabolic needs. This property of enzyme to be dually located inside the cell is often referred to as 'ambiquity'.
The mutual affinity of protein pairs is encoded in their respective sequences and structures, while their potential association or separation is effected through simple physico-chemical determinants of their local environment. The latter are believed to be achieved through the 'interpretation' of variable signals in the global environment (extra- or intra-cellular) by proper signal transduction.
last update, Dec 1999 - Claude Aflalo - suggestions are welcome...