Coenzyme

A coenzyme is the low molecular weight non-protein portion of enzymes. A coenzyme usually represents the activity centre of an enzyme. The coenzyme combines with the non-active enzyme protein (apoenzyme) to form the active enzyme protein (holoenzyme).

Many coenzymes are derivatives of vitamins and cannot be synthesized in the body. Others are synthesized in the body. They are usually derived from nucleotides.

Coenzymes almost always contain a phosphate group. They have a variety of functions, including the transfer of hydrogen in redox reactions, transamination and the transfer of methyl groups.

In cosmetics the coenzymes A and Q10 are used in external preparations. Coenzyme Q10 is propagated as anti-aging agent which neutralizes free radicals.