nicotinamide adenine dinucleotide, is composed of nucleosides of nicotinamide and adenine joined at their C-5' positions by a diphosphate group. The nicotinamide portion of NAD takes part in oxidation and reduction reactions.

flavin adenine dinucleotide, is composed of adenosine and a nucleoside containing riboflavin and the sugar alcohol ribotol. As in NAD, the two nucleosides are joined by a diphosphate link between their 5' carbons. Riboflavin, like nicotinamide, takes part in oxidation and reduction reactions.