All of the Following Are True Statements Concerning Enzymes EXCEPT

All of the following are true statements concerning enzymes EXCEPT:

A) They form a temporary intermediate compound with a substrate.
B) They can be used to catalyze a chemical reaction over and over again.
C) They function best at 37°C.
D) They are usually, but not always, proteins.
E) They can be denatured if the pH of their environment is too high or too low.