NUTRITIONAL ASPECTS: VITAMINS AND COENZYMES

 

A coenzyme is a small molecule that participates in an enzymatic reaction without really getting used up.   (It may get oxidized or reduced but that is easily reversible).   Often the structure of coenzymes is somewhat complex which means that our bodies do not have the enzymes to put them together and hence we consume the complex part of the coenzyme as a vitamin.   Then we often add something to the vitamin, sometimes a nucleotide, and it becomes a coenzyme.   Many of the enzymatic reactions discussed above use coenzymes derived from vitamins.   The table below summarizes this information:

VITAMIN	COENZYME	ENZYMES
Niacin	NAD+	Glyceraldehyde 3-phosphate dehydrogenase Pyruvate dehydrogenase Isocitrate dehydrogenase α-Ketoglutarate dehydrogenase Malate dehydrogenase
Niacin	NADP+	Glucose 6-phosphate dehydrogenase 6-Phosphogluconate dehydrogenase
Riboflavin	FAD	Pyruvate dehydrogenase α-Ketoglutarate dehydrogenase Succinate dehydrogenase
Thiamine	Thiamine Pyrophosphate	Pyruvate dehydrogenase α-Ketoglutarate dehydrogenase Transketolase (in pentose phosphate pathway)
Lipoic acid	Lipoic acid	Pyruvate dehydrogenase α-Ketoglutarate dehydrogenase
Pantothenate	Coenzyme A	Pyruvate dehydrogenase/citrate synthase α-Ketoglutarate dehydrogenase/succinyl CoA synthetase
Biotin	Biotin	Pyruvate carboxylase

return to top | previous page | next page