It's the coenzyme "nicotinamide adenine dinucleotide (NAD)", which is at the origin of the production of ATP. It's present in two forms: "an oxidized form (NAD+) and a reduced form (NADH)".

NAD, or nicotinamide adenine dinucleotide ... “NAD comes in two forms—NAD+ is the oxidized version which means it lost an electron; this is different from the NADH form (which has an extra ...

After combination with a dehydrogenase, it is reduced by a substrate (for example, lactate) with the formation of reduced cozymase and the oxidized product of the substrate (for example ...

They gained insights into cell metabolism by measuring nicotinamide adenine dinucleotide and nicotinamide ... gondii infection increased the ratio of bound enzymes and created a more oxidized ...