Many B vitamins are essential for the metabolism of energy yielding nutrients. They perform this function by binding to and promoting the activity of enzymes. When B vitamins perform in this way, they are ?

coenzymes

Explanation:

These are non-protein organic materials which binds with enzymes to catalyze a reaction. They can as well be referred to as a co factor, the reason been that the assist the activity of enzymes. Examples of coenzyme are vitamin B and S-adenosyl methionine. It is also very important to know that coenzymes cannot function alone.