n. (in biochemistry) a substance that helps to bring about oxidation of a reduced *substrate by accepting hydrogen ions.
(nicotinamide adenine dinucleotide) a *coenzyme that acts as a hydrogen acceptor in oxidation-reduction reactions, particularly in the *electron transport chain in cellular respiration. NAD and the closely related coenzyme NADP (nicotinamide adenine dinucleotide phosphate) are derived from nicotinic acid; they are reduced to NADH and NADPH, respectively.... nad
n. an enzyme, found mainly in plants but also present in leucocytes and milk, that catalyses the dehydrogenation (oxidation) of various substances in the presence of hydrogen peroxide (which acts as a hydrogen acceptor, being converted to water in the process).... peroxidase
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