45. Which of these staterents about the membrane proteins is true?
(A) An integral membrane protein can be extracted with a chelating agent that removes divalent cations.
(B) Peripheral membrane proteins are generally noncovalently bound to membrane lipids.
(C) Carbohydrate moieties of membrane glycoproteins are linked to the intracellular domain of the proteins.
(D) Peripheral membrane proteins may have functional units on both sides of the membrane.
(E) Glycosylphosphatidylinositols, abbreviated GPI, are complex glycolipids that attach some proteins to thecytosolic surface of the plasma membrane.