What is coenzyme

Coenzymes are small organic molecules that can transfer chemical groups from one enzyme to another. They are loosely combined with enzymes and are necessary for the activity of specific enzymes. Many vitamins and their derivatives, such as riboflavin, thiamine and folic acid, are coenzymes. These compounds cannot be synthesized by the human body and must be supplemented by diet. Different coenzymes can carry different chemical groups: nad+ or nadp+ carries hydrogen ions, coenzyme A carries acetyl, folic acid carries formyl, and S-adenosylmethionine can also carry formyl.