34. Which of the following description for regulating protein function is (are) CORRECT?
(A) Regulated synthesis and degradation of proteins is a fundamental property of cells.
(B) Protein functions could be regulated by covalent or noncovalent modification.
(C) Many of the regulations for protein activity are reversible.
(D) Noncovalent binding of calcium and GTP are widely used as allosteric switches to control protein
activity.
(E) Proteolytic cleavage irreversibly activates or inactivates some proteins.