Section 5.11: Multi-Enzyme Complexes

Many enzymes exist as parts of multi-enzyme complexes, where a sequence of catalyzed reactions are associated
Such complexes can increase the efficiency of the overall pathway, because products of one reaction can rapidly bind as substrates of the next reaction in a sequence, instead of diffusing away
In some cases, a complex may actually include a spatial tunnel to channel the product from one enzyme active site to another
An example of this is seen with tryptophan synthase, which catalyzes the final steps of tryptophan synthesis (Section 17.3F). The structure of the enzyme contains a tunnel to guide the indole ring to the active site of the final reaction, where it is exchanged with the side chain of serine