NMN comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Nicotinamide mononucleotide, abbreviated NMN, is a naturally occurring nucleotide. Its structure combines a nicotinamide base with a ribose sugar and a phosphate group. Within cells, NMN sits on the biosynthetic route that recycles nicotinamide back into nicotinamide adenine dinucleotide, or NAD+. Because NAD+ participates in redox reactions and signaling, enzymes that produce and consume it influence many metabolic processes. The compound is therefore best described as an intermediate rather than a final signaling molecule.
In the canonical salvage pathway, nicotinamide phosphoribosyltransferase, known as NAMPT, transfers a phosphoribosyl group to nicotinamide and releases NMN. A second enzyme, NMN adenylyltransferase, then attaches an adenylyl group to NMN to form NAD+. Alternative routes exist, including a pathway that uses nicotinamide riboside and its phosphorylated forms. The relative contribution of extracellular NMN to intracellular NAD+ pools remains an area of active investigation, and the roles of specific transporters and enzymes are not completely defined.
Nicotinamide mononucleotide, commonly abbreviated NMN, is a naturally occurring nucleotide found in the cells of many organisms. Its structure consists of a nicotinamide group linked to a ribose sugar that carries a phosphate group. NMN is an intermediate in the biosynthesis of nicotinamide adenine dinucleotide, or NAD+, a coenzyme involved in many metabolic reactions. The abbreviation usually refers to the beta anomer, though related forms can exist. In scientific literature, NMN is distinct from nicotinamide riboside, another NAD+ precursor.
In the NAD+ salvage pathway, the enzyme NAMPT converts nicotinamide and a phosphate-donor molecule into NMN. A second enzyme, NMNAT, then converts NMN into NAD+. Nicotinamide riboside can also enter this route after being converted to NMN by nicotinamide riboside kinases. Because NMN sits at a junction between precursor uptake and NAD+ formation, its cellular concentration is tightly linked to enzyme activity and tissue type. NAD+ participates in redox reactions, signaling, and DNA repair, and its levels decline with age in some animal models, though human evidence remains more limited and context-dependent.
| Property | Value | Notes |
|---|---|---|
| Chemical name | Nicotinamide mononucleotide | Abbreviated NMN |
| Molecular formula | C11H15N2O8P | Neutral form |
| Molar mass | 334.22 g/mol | Approximate value |
| Appearance | White to off-white powder | Typical solid form |
| Solubility | Water-soluble | May absorb moisture |
Nicotinamide mononucleotide, abbreviated NMN, is a naturally occurring nucleotide found in cells. Its structure consists of a nicotinamide ring linked to ribose phosphate, and the compound serves as an intermediate in the salvage pathway for nicotinamide adenine dinucleotide, or NAD+. In this pathway, nicotinamide phosphoribosyltransferase converts nicotinamide and phosphoribosyl pyrophosphate into NMN, after which NMN adenylyltransferase attaches an adenylate group to produce NAD+. Because NAD+ participates in redox reactions and signaling, NMN occupies a central position in cellular metabolism. The molecule is distinct from nicotinamide riboside, though the two are related in NAD+ precursor research.
Beyond its intracellular synthesis, NMN can be taken up from the extracellular environment, although the routes are still debated. Some evidence points to direct transport into cells through specific transporters, while other work suggests dephosphorylation to nicotinamide riboside followed by cellular uptake. Once inside, NMN can be converted to NAD+ by NMN adenylyltransferases; the relative contribution of these routes may differ by tissue, species, and experimental conditions. Researchers continue to investigate which mechanisms dominate in intact organisms and how they affect measured NAD+ levels. Direct measurement in tissues remains technically challenging because NMN can be rapidly metabolized during sample collection.
Two enzymatic steps define the canonical route from nicotinamide to NAD+. Nicotinamide phosphoribosyltransferase, known as NAMPT, produces NMN from nicotinamide and phosphoribosyl pyrophosphate. NMN adenylyltransferases, or NMNAT enzymes, then couple NMN with ATP to form NAD+. Whether intact NMN crosses cell membranes efficiently remains an active area of investigation; some studies propose direct transport, while others emphasize extracellular dephosphorylation to nicotinamide riboside followed by uptake. The relative contribution of each route likely depends on cell type, tissue, and experimental conditions.
Trace amounts of NMN have been reported in certain plant foods, including edamame, avocado, broccoli, cucumber, and cabbage. Reported concentrations vary widely because analytical methods differ and food matrices complicate extraction. Endogenous production in cells is generally considered more quantitatively important than dietary intake, though precise human turnover rates are difficult to establish. Commercial NMN for research or consumer products is commonly made through enzymatic synthesis or chemical phosphorylation routes. Regulatory classification differs by country; in some jurisdictions NMN is sold as a supplement, while in others it is treated as a novel food ingredient or restricted substance.
=== Burnup === "Burnup" is a measure of how much energy has been extracted from a given mass of heavy metal in fuel, often expressed (for power reactors) in terms of gigawatt-days per ton of heavy metal. Burnup is an important factor in determining the types and abundances of isotopes produced by a fission reactor. Burnup is distinct from the conversion or breeding ratio. A 2003 study of reduced-moderation water reactor fuel assemblies reported a configuration with an average core burnup of 38.2 GWd/t and a conversion ratio of 1.0, and another with 45 GWd/t and a conversion ratio of 0.97. In the past, breeder-reactor development focused on reactors with low breeding ratios, from 1.01 for the Shippingport Reactor running on thorium fuel and cooled by conventional light water to over 1.2 for the Soviet BN-350 liquid-metal-cooled reactor. Theoretical models of breeders with liquid sodium coolant flowing through tubes inside fuel elements ("tube-in-shell" construction) suggest breeding ratios of at least 1.8 are possible on an industrial scale. The Soviet BR-1 test reactor achieved a breeding ratio of 2.5 under non-commercial conditions.
Many AI systems are so complex that their designers cannot explain how they reach their decisions. Particularly with deep neural networks, in which there are many non-linear relationships between inputs and outputs. But some popular explainability techniques exist. It is impossible to be certain that a program is operating correctly if no one knows how exactly it works. There have been many cases where a machine learning program passed rigorous tests, but nevertheless learned something different from what the programmers intended. For example, a system that could identify skin diseases better than medical professionals was found to actually have a strong tendency to classify images with a ruler as "cancerous", because pictures of malignancies typically include a ruler to show the scale. Another machine learning system designed to help effectively allocate medical resources was found to classify patients with asthma as being at "low risk" of dying from pneumonia. Having asthma is actually a severe risk factor, but since the patients having asthma would usually get much more medical care, they were relatively unlikely to die according to the training data. The correlation between asthma and low risk of dying from pneumonia was real, but misleading. People who have been harmed by an algorithm's decision have a right to an explanation. Doctors, for example, are expected to clearly and completely explain to their colleagues the reasoning behind any decision they make.
In addition, this allowed Germany to gain control of Czech armament (particularly, the Škoda Works), and get rid of the threat of the Czech army and airfields, which were easily in range of Germany. On 8 March 1939, Hitler met with Wilhelm Keppler, the NSDAP's economic expert, where he spoke about his wish to occupy Czecho-Slovakia for economic reasons, saying that Germany needed its raw materials and industries. Hitler totally ignored the agreements of the Munich Agreement and scheduled a German invasion of Bohemia and Moravia for the morning of 15 March. In the interim, he negotiated with the Slovak People's Party and with Hungary to prepare the dismemberment of the republic before the invasion. On 13 March, he invited Tiso to Berlin and on 14 March, the Slovak Diet convened and unanimously declared Slovak independence. Carpatho-Ukraine also declared independence but Hungarian troops occupied and annexed it on 15 March and a small part of eastern Slovakia as well on 23 March.
Sources: en.wikipedia.org
In silico PCR (digital PCR, virtual PCR, electronic PCR, e-PCR) refers to computational tools used to calculate theoretical polymerase chain reaction results using a given set of primers (probes) to amplify DNA sequences from a sequenced genome or transcriptome. In silico PCR was proposed as an educational tool for molecular biology. Intersequence-specific PCR (ISSR): a PCR method for DNA fingerprinting that amplifies regions between simple sequence repeats to produce a unique fingerprint of amplified fragment lengths. Inverse PCR: is commonly used to identify the flanking sequences around genomic inserts. It involves a series of DNA digestions and self ligation, resulting in known sequences at either end of the unknown sequence. Ligation-mediated PCR: uses small DNA linkers ligated to the DNA of interest and multiple primers annealing to the DNA linkers; it has been used for DNA sequencing, genome walking, and DNA footprinting. Methylation-specific PCR (MSP): developed by Stephen Baylin and James G. Herman at the Johns Hopkins School of Medicine, and is used to detect methylation of CpG islands in genomic DNA. DNA is first treated with sodium bisulfite, which converts unmethylated cytosine bases to uracil, which is recognized by PCR primers as thymine. Two PCRs are then carried out on the modified DNA, using primer sets identical except at any CpG islands within the primer sequences. At these points, one primer set recognizes DNA with cytosines to amplify methylated DNA, and one set recognizes DNA with uracil or thymine to amplify unmethylated DNA.
The Supreme Soviet (successor of the Congress of Soviets) was nominally the highest organ of state authority for most of the Soviet history, at first acting as a rubber stamp institution, approving and implementing all decisions made by the party. However, its powers and functions were extended in the late 1950s, 1960s, and 1970s, including the creation of new state commissions and committees. It gained additional powers relating to the approval of the Five-Year Plans and the government budget. The Supreme Soviet elected a Presidium (successor of the Central Executive Committee) to wield its power between plenary sessions, ordinarily held twice a year, and appointed the Supreme Court, the Procurator General and the Council of Ministers (known before 1946 as the Council of People's Commissars), headed by the Chairman (Premier) and managing an enormous bureaucracy responsible for the administration of the economy and society. State and party structures of the constituent republics largely emulated the structure of the central institutions, although the Russian SFSR, unlike the other constituent republics, for most of its history had no republican branch of the CPSU, being ruled directly by the union-wide party until 1990. Local authorities were organized likewise into party committees, local Soviets and executive committees. While the state was a de jure federation with a nominally federal constitution, the party was de facto centralized and unitary. The state security police (the KGB and its predecessor agencies) played an important role in Soviet politics.
=== Systematics === The emu was long classified, with its closest relatives the cassowaries, in the family Casuariidae, part of the ratite order Struthioniformes. An alternate classification was proposed in 2014 by Mitchell et al., based on analysis of mitochondrial DNA. This splits off the Casuariidae into their own order, the Casuariiformes, and includes only the cassowaries in the family Casuariidae, placing the emus in their own family, Dromaiidae. The cladogram shown below is from their study.
Sources: en.wikipedia.org
NMN is nicotinamide mononucleotide, a nucleotide intermediate in NAD+ biosynthesis. It occurs naturally in cells and is also produced commercially as a supplement ingredient.
No. NMN is a precursor that can be converted into NAD+, while NAD+ is a dinucleotide coenzyme involved in redox reactions and signaling.
Small amounts have been reported in foods such as edamame, avocado, broccoli, and milk. Dietary amounts are generally much lower than those used in research studies.
Nicotinamide mononucleotide is a nucleotide intermediate in the biosynthesis of NAD+. It consists of nicotinamide attached to a ribose phosphate unit. NMN occurs naturally in cells and is present at low levels in some foods.