which is the organic molecule that is sometimes required for certain enzyme activity?
Coenzyme [edit]. A coenzyme is a small, organic, non-protein molecules that carries chemical groups between enzymes. It is the cofactor for the enzyme and does not form a permanent part in the enzyme's structure. Sometimes, they are called cosubstrates and are considered substrates that are loosely bound to the enzyme. In metabolism, coenzymes play a role in group-transfer reactions, such as ATP and coenzyme A, and oxidation-reduction reactions, such as NAD+ and coenzyme Q10. Coenzymes are frequently consumed and recycled.