Identify all statements that accurately describe the structure of the pyruvate dehydrogenase (PDH) complex.

(A) A regulatory kinase and phosphatase are part of the mammalian PDH complex.

(B) Several copies each of E1 and E3 surround E2.

(C) E2 contains three domains.

(D) The core of the complex is made up of several copies of E2.

(E) The complex contains multiple copies of E2 and single copies of several other enzymes.

Answer: (A). A regulatory kinase and phosphatase are part of the mammalian PDH complex.

(B). Several copies each of E1 and E3 surround E2.

(C). E2 contains three domains.

(D). The core of the complex is made up of several copies of E2.

therefore options A, B, C and D are correct.

Explanation: In eukaryotes, pyruvate dehydrogenase (PDH) complex is closely regulated by kinase (pyruvate dehydrogenase kinase, PDK) and phosphatase (pyruvate dehydrogenase

phosphatase, PDP). Deactivation and activation leads to the regulation.

In Eukaryotes, several copies of the E1 (pyruvate dehydrogenase) and the E3 (dihydrolipoyl dehydrogenase) bind specifically to the surface of the core of the complex E2 (dihydrolipoyl transacetylase).

Dihydrolipoyl transacetylases have a distinct multidomain structure which consists of 3 lipoyl domains, an interaction domain, and lastly, the catalytic domain. Dihydrolipoyl transacetylase enzymes can arrange into either a cubic or dodecahedral shape.