NAD refers to Nicotinamide adenine dinucleotide, found in all living cells, NAD with the CAS NO. of 53-84-9 and the chemical formula of C21H27N7O14P2 is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other nicotinamide NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen), respectively.
In metabolism, nicotinamide adenine dinucleotide is involved in redox reactions, carrying electrons from one reaction to another. The cofactor is, therefore, found in two forms in cells: NAD+ is an oxidizing agent – it accepts electrons from other molecules and becomes reduced. This reaction, also with H+, forms NADH, which can then be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD. However, it is also used in other cellular processes, most notably as a substrate of enzymes in adding or removing chemical groups to or from, respectively, proteins, in posttranslational modifications. Because of the importance of these functions, the enzymes involved in NAD metabolism are targets for drug discovery.
In organisms, NAD can be synthesized from simple building-blocks (de novo) from either tryptophan or aspartic acid, each a case of an amino acid; alternatively, more complex components of the coenzymes are taken up from nutritive compounds such as niacin; similar compounds are produced by reactions that break down the structure of NAD, providing a salvage pathway that “recycles” them back into their respective active form.
Some NAD is converted into the coenzyme nicotinamide adenine dinucleotide phosphate (NADP); its chemistry largely parallels that of NAD, though predominantly its role is as a cofactor in anabolic metabolism.
In general, there are three main manufacture methods for NAD preparation utilized by NAD manufacturers in the world such as chemical or enzymatic synthesis, and fermentation biosynthesis. And at present, the NAD manufacturers are located worldwide including China, America, Japan and German.