The short version of mass spectrometry fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-09. Anything still debated is marked as such rather than presented as settled.
NAD+ is a dinucleotide composed of two nucleotides joined by a pyrophosphate linkage. One nucleotide contains adenine, and the other contains nicotinamide. The oxidized form carries a positive charge on the nicotinamide ring and is abbreviated NAD+. It functions as a cofactor in hydride-transfer reactions, accepting electrons in catabolic pathways. In cells, it interconverts with reduced NADH, forming a redox couple central to energy metabolism. The molecule is water-soluble and does not cross cell membranes freely without specific transport or precursor pathways.
The nicotinamide ring undergoes reversible reduction at the para position, converting NAD+ to NADH. This reaction transfers a hydride equivalent, not a free hydrogen atom or electron alone. Because the redox pair has a defined reduction potential, it links oxidation of fuels to respiratory chain activity. Many dehydrogenases use NAD+ as a co-substrate and produce NADH. The ratio of NAD+ to NADH reflects metabolic state and influences flux through several pathways.
Nicotinamide adenine dinucleotide, commonly abbreviated NAD+, is a coenzyme present in all living cells. The molecule consists of two nucleotides linked by phosphate groups, with adenine and a nicotinamide ring as its principal features. In its oxidized form, the nicotinamide ring can accept a hydride ion, becoming NADH. This reversible conversion places NAD+ at the center of many electron-transfer reactions. Its role as a redox carrier is well established across bacteria, plants, fungi, and animals.
Beyond redox chemistry, NAD+ acts as a substrate for several enzyme families. ADP-ribosyltransferases, sirtuins, and CD38 ectoenzymes cleave the molecule into nicotinamide and ADP-ribose or related products. These reactions connect NAD+ availability to processes such as DNA repair, chromatin modification, and calcium signaling. Because the coenzyme is used in both electron transfer and signaling, cells maintain separate pools in compartments including the cytosol, mitochondria, and nucleus. The relative sizes and regulation of those pools remain active areas of study.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | Nicotinamide adenine dinucleotide | Oxidized dinucleotide form |
| CAS Registry Number | 53-84-9 | Common entry for beta-NAD+ |
| Molecular formula | C21H27N7O14P2 | Free acid form |
| Molar mass | 663.43 g/mol | Calculated for free acid |
| Water solubility | Freely soluble | Charged dinucleotide; less soluble in organic solvents |
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a dinucleotide composed of two nucleotides joined by phosphate groups. One nucleotide contains adenine; the other contains nicotinamide. The molecule exists in oxidized (NAD+) and reduced (NADH) forms, and the reversible hydride transfer between them underlies many metabolic oxidation-reduction reactions. In cells, NAD+ serves as an electron acceptor in pathways such as glycolysis, the citric acid cycle, and oxidative phosphorylation. Its concentration and redox ratio vary by compartment, tissue, and metabolic state.
Beyond redox chemistry, NAD+ is consumed as a substrate by enzymes that transfer ADP-ribose or remove acetyl groups. Sirtuins use NAD+ in deacylation reactions, poly(ADP-ribose) polymerases use it in DNA damage responses, and CD38 hydrolases convert it to signaling metabolites. Because these enzymes compete for the same pool, changes in NAD+ availability can influence multiple cellular processes. The relative contribution of each consumption route differs by cell type and condition, and precise quantitative links remain an active area of study.
NAD+ is relatively unstable in aqueous solution, especially at neutral or alkaline pH and at elevated temperatures. It is typically stored dry, protected from light and moisture, and kept cold or frozen for long-term use. Solutions are often prepared fresh or buffered to mildly acidic pH to slow hydrolysis. Repeated freeze-thaw cycles can reduce integrity. Laboratories may verify concentration using ultraviolet absorbance at 259 nm or by enzymatic assay. These handling practices are general laboratory conventions rather than universal rules.
Research on NAD+ often examines changes with age, diet, exercise, and disease states, but causal relationships are difficult to establish. Some studies measure NAD+ levels, while others assess enzyme activity or downstream markers. In the literature, terms such as "NAD+ decline" and "NAD+ boosting" appear in both scientific and commercial contexts, sometimes without precise definitions. Whether changes in measured NAD+ directly produce health effects remains an open question. Results from cells, animals, and humans cannot be assumed to translate directly.
== Prognosis == Symptoms usually get worse over the course of two weeks, then stabilize, and finally begin to improve. Motor problems, including chorea, settle within an average of 2–3 months. Recurrence is seen in 16–40% of cases. It is sometimes but not always associated with a rise in ASO titre or other evidence of new streptococcal infection. Recurrence is more likely with poor compliance with penicillin prophylaxis. It is more likely if there is failure to remit within 6 months of onset. Recurrence is associated in women with pregnancy (chorea gravidorum) and with female hormone treatment, although the onset of chorea can be delayed by months or more. Intramuscular penicillin given every 2–3 weeks is superior to a 4 weekly regime for preventing relapse, but a risk assessment may conclude that twice daily oral penicillin is sufficiently effective, less painful for the child, and less demanding on the family. Higher recurrence rates are seen with the longest follow up. Relapse can be seen 10 years or more after the initial episode, so might be underestimated by series with shorter follow up. Recurrence is usually only chorea, even if the original case was associated with rheumatic fever. There are two total reports of heart disease worsening after recurrence of chorea. The Thailand study also had 2 cases where carditis, which had improved after initial diagnosis, came back again. Some suggest that recurrent chorea is a different disease altogether. 10% reported long-term tremor in one study (10 years follow up).
== Relationship of GHRH and somatostatin == The actions of GHRH are opposed by somatostatin (growth-hormone-inhibiting hormone). Somatostatin is released from neurosecretory nerve terminals of periventricular somatostatin neurons, and is carried by the hypothalamo-hypophyseal portal circulation to the anterior pituitary where it inhibits GH secretion. Somatostatin and GHRH are secreted in alternation, giving rise to the markedly pulsatile secretion of GH.
The spray is a combination of local anaesthetics lidocaine and prilocaine in a metered-dose aerosol that is sprayed directly on the penis to numb sensations. It was developed by the same group that invented the erectile dysfunction drug sildenafil. The drug was approved in Europe and was released in the UK market in November 2016 and within the EU will be marketed by, early in 2017 In the United States, the Food and Drug Administration (FDA) is expected to approve the drug in 2018.
Sources: en.wikipedia.org
=== 1997–present: CKE, Imasco, Plamondon Companies === In 1997, CKE Restaurants acquired Hardee's from Imasco, but Imasco retained the Roy Rogers trademark and franchise system. The Riese family, which owned 18 Roy Rogers restaurants, sued CKE Restaurants and Imasco for $10 million in 1997, claiming the Roy Rogers chain has been destroyed through "a series of marketing errors of epic proportions." Imasco sold Roy Rogers to Plamondon Enterprises (now Plamondon Companies) in 2002, after three years of negotiation. Roy Rogers was relaunched as Roy Rogers Franchise Company, LLC. Plamondon had already opened the first new Roy Rogers restaurant in Frederick, Maryland, in 2000. At the time of the sale, there were 63 existing Roy Rogers franchises in nine states. In 2021, Roy Rogers announced a strategy to build concentrically out of core markets in the Mid-Atlantic, like Maryland, Virginia, West Virginia, and Pennsylvania. The growth circle would slowly get bigger and include New York, the Eastern Seaboard, and states like Ohio, Tennessee, Florida, Texas, Louisiana, Mississippi, Alabama, and Georgia. The next year, the company announced a new partnership with One Holland Corporation restaurant group and planned to open 10 new Roy Rogers locations over the next six years in the Cincinnati metropolitan area. The new locations would be in Hamilton, Butler, and Clermont counties in Southwest Ohio; Boone, Kenton, and Campbell counties in Northern Kentucky; and Dearborn County in Southeast Indiana. Despite these plans, a spokesperson for One Holland Corp.
=== Phase 3 === Brexpiprazole (Rexulti) – dopamine D2 and D3 receptor partial agonist, serotonin 5-HT1A receptor partial agonist, serotonin 5-HT2A 5-HT2B, and 5-HT7 receptor antagonist, α1- and α2-adrenergic receptor antagonist, and atypical antipsychotic Cariprazine (Reagila, Symvenu, Vraylar; MP-214, RGH-188, WID-RGC20) – dopamine D2 and D3 receptor partial agonist, serotonin 5-HT1A receptor partial agonist, serotonin 5-HT2B receptor antagonist, and atypical antipsychotic Lumateperone (Caplyta) – dopamine D1 and D2 receptor antagonist, serotonin 5-HT2A receptor antagonist, α1-adrenergic receptor antagonist, serotonin reuptake inhibitor, and atypical antipsychotic Lurasidone (Latuda) – dopamine D2 and D3 receptor antagonist, serotonin 5-HT1A receptor partial agonist, serotonin 5-HT2A and 5-HT7 receptor antagonist, α2C-adrenergic receptor antagonist, and atypical antipsychotic Tasimelteon (Hetlioz) – melatonin MT1 and MT2 receptor agonist
== Sources == The compound arenobufagin is one of the major components of certain toad toxins. It is derived from the dried skin of giant toads, such as Bufo gargarizans and Bufo melanostictus Suhneider. Arenobufagin is specifically secreted by Rhinella arenarum, which is found in South America. The toxin of these toad species contains about 1.75% of arenobufagin. The other major part of the venom consists mostly of similar looking bufagins, which are all toxic steroids. Toads produce their toxin when they are scared, injured, or provoked, as a defense mechanism against being eaten by their predators.
Sources: en.wikipedia.org
NAD+ is the oxidized form, while NADH is the reduced form carrying an added hydride. The two form a redox pair that cells use in many energy-yielding reactions.
NAD+ is a small organic cofactor, not a protein or enzyme. It binds temporarily to enzymes such as dehydrogenases to assist electron transfer.
Intact NAD+ is generally not taken up efficiently by most cells because it is charged and water-soluble. Cells often rely on precursors such as nicotinamide or nicotinamide riboside to produce NAD+ internally.
NAD+ is a coenzyme found in living cells and is the oxidized form of nicotinamide adenine dinucleotide. It accepts electrons in redox reactions and also serves as a substrate for certain signaling and repair enzymes.