Protein kinases are enzymes that catalyze phosphorylation of target proteins at specific sites,whereas protein phosphatases catalyze removal of phosphate(s)from phosphorylated proteins.Phosphorylation and dephosphorylation can function as an on-off switch for a protein's activity,most likely through
A)the change in a protein's charge leading to a conformational change. B)the change in a protein's charge leading to cleavage. C)a change in the optimal pH at which a reaction will occur. D)a change in the optimal temperature at which a reaction will occur. E)the excision of one or more peptides.