The pyruvate dehydrogenase (PDH) complex catalyzes the oxidative decarboxylation of pyruvate to acetyl−CoA and CO 2 . CO2. Multi

ple copies of pyruvate dehydrogenase (E1), dihydrolipoyl transacetylase (E2), and dihydrolipoyl dehydrogenase (E3) along with five cofactors form the PDH complex. Biochemists have studied the PDH complex for decades, in part due to its interesting use of substrate channeling during catalysis. What is the benefit of substrate channeling?
The PDH active site forms in the hydrophobic core of the complex instead of a surface-exposed region.
Reaction progress is not limited by the diffusion constant.
Intermediates of a multistep reaction sequence do not dissociate from the enzyme complex.
The PDH complex sequesters excess substrate to use at later time.
Every intermediate or product made by the PDH complex enters the citric acid cycle as a substrate.