Thiamine pyrophosphate (tpp) is a coenzyme derived from vitamin b1 that is used by the enzyme pyruvate dehydrogenase to convert pyruvate to acetyl coa. tpp has a relatively acidic proton that can prod

Thiamine pyrophosphate (tpp) is a coenzyme derived from vitamin b1 that is used by the enzyme pyruvate dehydrogenase to convert pyruvate to acetyl coa. tpp has a relatively acidic proton that can produce a carbanion which can act as an electron sink and aid in the decarboxylation of α–keto acids. the first step of the pyruvate dehydrogenase mechanism is the reaction of pyruvate with tpp, followed by decarboxylation. this gives an intermediate that can donate a two-carbon unit to the lipoamide prosthetic group to form acetyl lipoamide. identify the second intermediate by dragging in the correct structure.