Nadid

Beschreibungβ-Nicotinamide adenine dinucleotide (NAD+) plays a major role in metabolism as a cofactor and mobile electron acceptor. NAD+ is a required oxidizing cosubstrate for many enzymes. It is reduced to NADH (Cat# N-035) which carries electrons to the electron transport chain for subsequent oxidative phorphorylation and ATP production. NAD+ is capable of donating ADP-ribose moieties to a protein, producing nicotinamide in the process. Sirtuin enzymes use NAD+ as a substrate to deacetylate proteins and direct activity between the nucleus and mitochondria. NAD+ is regenerated by fermentation and by oxidative phosphorylation.

Historyβ-Nicotinamide adenine dinucleotide was first discovered by British biochemists Arthur Harden and William John Young in 1906. They observed that the addition of boiled and filtered yeast extract significantly increased the rate of alcoholic fermentation in unboiled yeast extracts. They named the unidentified factor responsible for this effect a coferment. By extensively purifying it from yeast extracts, Hans von Euler-Chelpin identified this heat-stable factor as a nucleotide sugar phosphate. In 1936, German scientist Otto Heinrich Warburg demonstrated the role of this nucleotide coenzyme in hydride transfer and determined the nicotinamide portion as the site of redox reactions. Vitamin precursors of NAD+ were first identified in 1938, when Conrad Elvehjem showed that liver has an "anti-black tongue" activity in the form of nicotinamide. Then, in 1939, he provided the first strong evidence that niacin is used to synthesize NAD+.