NAD+

NAD⁺ is the only non-peptide small molecule in this catalogue apart from the diluent. It is a pyridine dinucleotide coenzyme — a substrate and cofactor for a large number of enzymes, not a ligand for any receptor — and it behaves quite differently from the peptides in storage and handling.

Structure

Two nucleotides joined tail to tail through a pyrophosphate bridge: adenosine monophosphate on one side and nicotinamide mononucleotide on the other. The redox chemistry happens entirely at the nicotinamide ring — the adenine half is structural and recognition-bearing.

The β designation refers to the anomeric configuration of the nicotinamide ribose. The α anomer exists, is a distinct compound, and is not the biologically relevant form — which is why reference catalogues write “β-NAD” rather than simply “NAD”.

Two disambiguations that matter

NAD⁺ is not NADH. The oxidised and reduced forms are different compounds with different registry numbers, different masses, different colour and dramatically different stability. NADH is markedly less stable, particularly under acidic conditions, where NAD⁺ is comparatively robust — the pH stability profiles are essentially inverted between the two. Specifications for the pair are cross-contaminated in supplier listings often enough to be worth checking every time.

Neither is NADP. NADP⁺ and NADPH carry an additional 2′-phosphate on the adenosine ribose and are separate compounds again. Registry numbers circulating incorrectly for NAD⁺ include 606-68-8 (NADH disodium) and 24292-60-2 and 1184-16-3 (NADP salts). None of these is NAD⁺.

Free acid or sodium salt

NAD⁺ is supplied either as the free acid or as a sodium salt, most commonly the disodium. The salt is heavier — around 707 g/mol for the disodium against 663.43 for the free acid — and is substantially more hygroscopic.

A complication worth knowing: the disodium salt has no clearly registered CAS number that we could verify from an authoritative source, whereas the free acid does. That asymmetry is itself a reason to read the certificate rather than the label.

We do not publish a single registry number for this listing. The certificate of analysis for the lot states which form it is, and the form determines both the molar quantity in the vial and how aggressively it must be kept dry.

Specification and characterisation

• Purity by HPLC against a reference standard, typically with UV detection.
• A₂₆₀ spectrophotometry. NAD⁺ absorbs strongly at 260 nm via the adenine. The A₂₆₀/A₃₄₀ ratio is the classical purity check: NAD⁺ has no absorbance at 340 nm, while NADH absorbs strongly there. Measurable 340 nm absorbance in a NAD⁺ preparation indicates reduced-form contamination, and this is a two-minute test on any UV spectrophotometer.
• Enzymatic assay. Coupling to an NAD-dependent dehydrogenase — alcohol dehydrogenase is conventional — measures functional cofactor rather than merely intact-looking material.
• Water content by Karl Fischer. Not a formality for a hygroscopic compound; it directly determines how much of the vial mass is the substance.
• Free nicotinamide and ADP-ribose, the principal hydrolytic degradation products.
• Sodium content where the salt form is supplied, establishing the stoichiometry.

Handling and stability

Keep it desiccated. Both forms are hygroscopic and the sodium salt strongly so. Absorbed water both dilutes the material gravimetrically and accelerates hydrolysis. Equilibrate the vial to room temperature in a desiccator before opening, weigh promptly, and reseal.

The stability profile is specific and worth stating plainly:

• Very labile in alkaline solution. This is the dominant degradation route and the most common handling error. Do not prepare or store NAD⁺ in alkaline buffer.
• Markedly more stable at acidic to neutral pH — the opposite of NADH, which is acid-labile.
• Heat-sensitive in solution.
• Light-sensitive in solution; store solutions in the dark.

Prepare solutions fresh where the work allows it.

Related compounds in this library

NAD⁺ has no structural relative among the peptides. It sits alongside SS-31 and MOTS-c under mitochondrial research as a thematic grouping only — chemically it has nothing in common with either.

References

Chemical, specification and analytical sources. This list is deliberately limited to chemistry and analytical references.

• Sigma-Aldrich, β-nicotinamide adenine dinucleotide — specification, purity criteria, storage
• Cayman Chemical, NAD⁺ record — formula, molecular weight, stability
• PubChem, NAD — structure and registry data
• NIST Chemistry WebBook — physical property data

Cosmic Aminos supplies this material as a laboratory reagent for in-vitro research use only. It is not a drug, food, cosmetic or dietary supplement, is not approved by the Food and Drug Administration for any use, and is not for human or veterinary consumption. No dosing, administration or preparation guidance is provided.