#Question id: 10308
#Unit 6. System Physiology – Plant
Oxidative decarboxylation of pyruvate to acetyl-CoA by the
PDH complex, how the pyruvate dehydrogenase complex carries out the five
consecutive reactions in the decarboxylation and dehydrogenation of pyruvate?
A) Pyruvate reacts with the bound thiamine pyrophosphate
(TPP) of pyruvate dehydrogenase, undergoing decarboxylation to the hydroxyethyl
derivative
B) A transesterification in which the —SH group of CoA
replaces the —SH group of E2 to yield acetyl-CoA and the fully reduced
(dithiol) form of the lipoyl group
C) The reduced FADH2 of E3 transfers a hydride ion to NAD1 ,
forming NADH, the enzyme complex is now ready for another catalytic cycle
D) The transfer of two electrons and the acetyl group from
TPP to the oxidized form of the lipoyllysyl group of the core enzyme,
dihydrolipoyl transacetylase, to form the acetyl thioester of the reduced
lipoyl group
E) Dihydrolipoyl dehydrogenase promotes transfer of two
hydrogen atoms from the reduced lipoyl groups of E2 to the FAD prosthetic group
of E3 , restoring the oxidized form of the lipoyllysyl group of E2
Find out the correct sequence of action of this complex
enzyme?
