A coenzyme is an organic non–protein molecule such as derivative of a water soluble vitamin. A coenzyme binds or attaches with a protein molecule (referred to as an apoenzyme). The coenzyme and the apoenzyme together are referred to as a holoenzyme or "an active enzyme".
Coenzymes are often referred to as cofactors. Although the terms can be used synonymously, be aware that the term "cofactor" is also used in haematology as a reference to "factors" in the blood (eg. coagulation factors) and other biochemical systems.
In summary, both coenzymes and cofactors assist enzymes by increasing their rates of reaction (lowering their required energy of activation).
|Coenzyme A||Coenzyme Q||Coenzyme B12|