factorvitamin

Factorvitamin is a term occasionally used in nutrition and biochemistry to describe vitamins that function as essential cofactors or coenzymes in metabolic reactions. It is not a formal category in major dietary guidelines, and its use varies among authors. The term highlights that vitamins enable catalytic steps in metabolism, not merely energy provision.

Most factorvitamins are B vitamins and certain fat-soluble vitamins, which participate as enzyme cofactors or co-substrates. Examples include thiamine (B1) as thiamine pyrophosphate in decarboxylation reactions; riboflavin (B2) as FAD; niacin (B3) as NAD/NADP; pantothenic acid (B5) as part of CoA; biotin (B7) as a cofactor for carboxylases; folate (B9) in one-carbon transfers; and cobalamin (B12) in methyl transfer reactions. Vitamin K acts as a cofactor for gamma-carboxylation; vitamin C functions as a cofactor for certain enzymes in collagen synthesis. Vitamin A and vitamins D and E also have roles related to enzyme function in various tissues.

Deficiency of factorvitamins disrupts these enzymatic processes and can cause symptoms such as neuropathy, anemia, impaired DNA synthesis, or defective collagen formation. Recommended intakes follow standard dietary guidelines; excessive intake for some vitamins can be toxic.

Because factorvitamin is not standardized, it is mainly used to explain the catalytic roles of vitamins rather than to define a fixed class. See also vitamins, cofactors, and coenzymes.