Abstract
Vitamins are defined as essential organic micronutrients that are not synthesized by mammals. Coenzymes are organic compounds with low molecular weight that are required to show enzyme activities by reversibly binding with their apoenzymes, and are derived mainly from compounds of vitamin B group. Most of coenzymes show various biofunctions besides their functions as coenzymes. Accordingly, it is more appropriate to regard them as effective biofactors. Pyridoxal phosphate serves as an inhibitor of catepsins, and regulates the gene expression. Several novel built-in coenzymes such as topaquinone and lysine tyrosylquinone have been demonstrated in mammalian and microbial enzymes.
