This page discusses the roles of nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) as essential coenzymes in cellular processes. NADP differs from NAD by a...This page discusses the roles of nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) as essential coenzymes in cellular processes. NADP differs from NAD by an extra phosphate and both act as redox agents, gaining electrons and releasing protons. NAD is key in glycolysis and the citric acid cycle, while NADP is produced during photosynthesis and is used in the Calvin cycle and anabolic reactions in plants and animals.