Which of the following statements about enzyme cofactors are correct?
A.
Many of the reactions within these five classes are facilitated by cofactors, in the form of coenzymes and metal ions (vitamin B 12 , S–adenosylmethionine, folate, nicotinamide, and Fe 2+ are some examples).
B.
Cofactors bind to enzymes—in some cases reversibly, in other cases almost irreversibly—and give them the capacity to promote a particular kind of chemistry.
C.
Most cofactors participate in a narrow range of closely related reactions.
D.
The cofactors provide another way to organize the study of biochemical processes, given that the reactions facilitated by a given cofactor generally are mechanistically related.