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

a. The core of the complex is made up of several copies of E2.

b. E2 contains three functionally distinct domains.

c. Several copies each of E1 and E3 surround E2.

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

e. The complex contains multiple copies of E2 and single copies of several other enzymes.