All the vitamins of the B-complex are known to function as co-enzymes. Co-enzyme functions, however, have not been defined for the fat-soluble vitamins or for ascorbic acid.
Co-enzymes are substances found in food that are necessary for an enzyme to function. They are organic compounds, often B-vitamin derivatives that combine with an inactive enzyme to form and active one. Since human bodies cannot manufacture co-enzymes, it must be obtained from the diet.
Vitamin B12, vitamin B6 and folate function as con-enzymes involved in one-carbon metabolism. Vitamin B12 is a cofactor for two enzymes, methionine synthase and 1-methylmalonyl-CoA. These enzymes are essential for blood formation and neurologic function.
Other B-complex vitamins are:
Thiamin (B1) – co-enzyme functions in metabolism chain of carbohydrates and branched amino acids
Riboflavin (B2) – co-enzyme functions in oxidation and reduction reaction
Niacin – Co-substrate/co-enzyme for hydrogen transfer with numerous dehydrogenases
Pantothenic acid - constituent of co-enzyme A and phosphopantetheine involved in fatty acid metabolism
Biotin –con-enzyme functions in bicarbonate-dependent
B-complex vitamins function as co-enzyme
