NAD+ sits apart from everything else in this catalogue. It is not a peptide, has no sequence and no residues, and none of the analytical habits built around peptides transfer to it cleanly. It is a small organic cofactor, and reading a specification for one means reading different lines.

Identity

  • Molecular formula: C21H27N7O14P2
  • Molecular weight: approximately 663 g/mol
  • PubChem CID: 5892

The name is an abbreviation of nicotinamide adenine dinucleotide, and the structure follows the name: two nucleotides joined through their phosphate groups, one carrying nicotinamide and the other adenine.

The plus sign is part of the name

NAD+ and NADH are the same molecule in two states. The cofactor works by accepting and giving up electrons, and the notation distinguishes the oxidised form from the reduced one. Writing NAD without a sign is ambiguous, because it does not say which state is meant.

This is not pedantry over notation. The two forms differ in mass and in how they behave analytically, so a specification that omits the sign has left out part of the identity.

What it does in a cell

The cofactor carries electrons between reactions, which places it in the centre of energy metabolism. Beyond that role it is consumed as a substrate by several families of enzymes, so the cell both recycles it and spends it, and the pool has to be replenished. (Reference: Cantó et al., 2015)

Because it is both a recycled carrier and a consumed substrate, its concentration is regulated rather than fixed, and how that balance is maintained has been reviewed in detail. (Reference: Katsyuba et al., 2020) (Reference: Belenky et al., 2007)

These are laboratory and model-based observations. NAD+ is supplied strictly as a research compound, and nothing here describes use in people or animals.

Four related molecules, four different compounds

The abbreviations in this corner of a catalogue are close enough to misread at a glance, and each names a distinct substance with its own mass.

  • NAD+ and NADH: the oxidised and reduced forms of the same cofactor.
  • NADP+ and NADPH: the same pair carrying an additional phosphate, which makes them different molecules used by different enzymes.

A specification that names one of the four is naming something a mass measurement can confirm, since the phosphate and the hydride each change the mass by an amount an instrument resolves without difficulty. A listing that says only NAD has not specified which of them it means.

Where the compound comes from

Research-grade material is produced by chemical or enzymatic synthesis and purified, not extracted in any quantity from tissue. That matters for the impurity profile: what ends up alongside the product reflects the route used to make it and the purification that followed, which is the same logic that applies to a synthetic peptide even though the chemistry has nothing in common with solid-phase synthesis.

It also means the compound carries no sequence to verify and no counterion story of the kind that complicates a peptide's weighed mass. The salt form, where one is present, is stated on the specification instead.

Why the analytical questions are different

For a peptide, identity means comparing a measured mass against one calculated from a sequence, and purity means resolving deletion sequences that differ by a single residue. Neither applies here.

NAD+ is a defined small molecule made by chemical or enzymatic routes, not assembled residue by residue, so there are no deletion sequences. Its likely impurities are its own relatives: the reduced form, the phosphorylated version, and breakdown products from hydrolysis of the linkage between the two halves.

That changes what a chromatographic method has to separate. Related nucleotides are polar, and the reversed-phase conditions tuned for peptides are not automatically the right conditions for them.

It absorbs where peptides do not

The nicotinamide and adenine rings absorb ultraviolet light strongly, with a maximum near 260 nm that comes from the adenine. That is a different wavelength from the ones used for peptide work, where detection sits near 214 nm for the amide bond or 280 nm for aromatic side chains.

The reduced form adds a second absorbance band that the oxidised form lacks, which is the basis of the classic assay for following these reactions and a quick way to tell the two states apart.

It is less stable than a peptide in solution

The bond joining the two nucleotide halves is susceptible to hydrolysis, and the molecule is sensitive to both acid and base. In solution it degrades faster than a typical lyophilized peptide would, and warmth accelerates it.

The handling rules are therefore the ordinary ones applied with more attention: keep the dry material dry and cool, let a cold vial reach room temperature before opening so condensation does not form inside, and treat a solution as short-lived. Our guide to storing research peptides covers why the dry state is the stable one.

What a certificate should carry

The same principle as everywhere else, with the lines adjusted to the compound.

  • Identity confirmed against the formula and mass above, with the oxidation state stated.
  • Purity from a method suited to polar nucleotides, with the conditions named.
  • Water content, since a hygroscopic solid takes up moisture and the water is part of what you weigh.
  • A batch number tying all of it to the vial, which can be checked.

Our guide to reading a certificate of analysis covers the general case; the fields differ for a cofactor, and the logic does not.

Research use only

All products sold by Codex Research, including NAD+, are strictly for laboratory research and development. They are not for human or animal consumption and are not intended to diagnose, treat, cure, or prevent any disease.

The compound at Codex Research

NAD+, 1000 mg per vial · batch-verified, with its certificate of analysis.

Frequently asked questions

What is NAD+?

Nicotinamide adenine dinucleotide, a small organic cofactor built from two nucleotides joined through their phosphates. Its formula is C21H27N7O14P2 and its molecular weight is about 663 g/mol. It is not a peptide and has no sequence.

What does the plus sign mean?

It marks the oxidised form. NAD+ and NADH are the same molecule in two states, since the cofactor works by accepting and giving up electrons. Writing NAD without a sign leaves the state unspecified, and the two forms differ in mass.

Why is NAD+ analysed differently from a peptide?

Because it is a defined small molecule rather than a chain assembled residue by residue, so there are no deletion sequences. Its likely impurities are related nucleotides and hydrolysis products, which are polar and need different chromatographic conditions.

Is NAD+ stable in solution?

Less so than a lyophilized peptide. The bond joining its two halves is susceptible to hydrolysis and the molecule is sensitive to acid and base, so a solution should be treated as short-lived and kept cold.

Why does water content matter for NAD+?

Because a hygroscopic solid takes up moisture from the air, and that water is part of what you weigh. It is also the reason a cold vial should reach room temperature before being opened.

What should a certificate for NAD+ report?

Identity confirmed against the formula and mass with the oxidation state stated, purity from a method suited to polar nucleotides with the conditions named, water content, and a batch number tying all of it to the vial.

References

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