NAD⁺ (nicotinamide adenine dinucleotide) is a coenzyme composed of two nucleotides: one containing adenine and the other nicotinamide, joined through their phosphate groups. Its molecular formula is C₂₁H₂₈N₇O₁₄P₂, and it has a molar mass of approximately 664.4 g/mol in its oxidized form.