The hydroxyethyl group attached to TPP is oxidized and transferred: First two electrons. then the acety group formed are all transferred to the lipoyllysyl (硫辛酰赖氨酰) group of dihydrolipoyl transacetylase (E2). The li e lipo oyllysyl gro oup serves as both electron and acetyl carriers The acetyl group is then transferred (still catalyzed by E2) from acetyllipoamide to CoA-SH, forming acetyl-CoA The oxidized lipoamide group is then regenerated by the action of dihydrolipoyl dehydrogenase(E3), with electrons collected by FAd and then by nad• The hydroxyethyl group attached to TPP is oxidized and transferred: First two electrons, then the acetyl group formed are all transferred to the lipoyllysyl (硫辛酰赖氨酰）group of dihydrolipoyl transacetylase (E2 ). • The lipoyllysyl group serves as both electron and acetyl carriers. • The acetyl group is then transferred (still catalyzed by E2 ) from acetyllipoamide to CoA-SH,forming acetyl-CoA. • The oxidized lipoamide group is then regenerated by the action of dihydrolipoyl dehydrogenase (E3 ), with electrons collected by FAD and then by NAD+