Why is Pyruvate Dehydrogenase a Multienzyme Complex?
It is a multienzyme complex because it consists of multiple distinct active sites catalyzing distinct reactions. As I recall, there are three distinct active sites and the substrate is tethered and shifts from one active site to the next in the course of the reaction. A thiamine deficiency would ultimately prevent one of the reactions from occurring, which would completely block the reactions catalyzed by the enzyme.
