An Enzyme Undergoes a Mutation That Causes It to Lose $\rightarrow$

Multiple Choice

An enzyme undergoes a mutation that causes it to lose the ability to be regulated via phosphorylation. Which of the following mutations may lead to this loss of regulation? Assume that the overall structure is not altered by the mutation.

A) Ser $\rightarrow$ Thr
B) Thr $\rightarrow$ Ser
C) Tyr $\rightarrow$ Phe
D) Ser $\rightarrow$ Tyr