LC-MS/MS raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-06-27 and is reviewed periodically as new material appears.
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.
NMN is present in small amounts in various foods, including certain vegetables, fruits, and milk, though dietary quantities are generally low. Laboratory research often uses synthetic or enzymatically produced NMN. The compound has drawn interest because NAD+ levels decline with age in some tissues and because restoring NAD+ may affect metabolism in animal models. Whether oral NMN produces meaningful NAD+ increases in humans and whether such changes translate into health benefits are not fully established.
Quality control for NMN materials typically includes identity, assay, impurity, and residual solvent tests. Certificates of analysis may report HPLC purity, water content, heavy metals, and microbial limits depending on the intended use. Because commercial NMN is sold as a research chemical or ingredient rather than a standardized drug in many jurisdictions, specifications can vary between suppliers. Independent verification can involve comparing retention time, mass spectrum, and NMR data against a reference standard. Open questions remain about how best to standardize purity claims and biological potency across different production methods.
Analytical identification of NMN usually combines chromatographic separation with mass spectrometric detection. High-performance liquid chromatography coupled to tandem mass spectrometry is common for quantifying NMN in biological matrices and finished materials. Because NMN and related nucleotides share similar masses and retention behavior, method development must resolve potential interferences such as nicotinamide riboside and NAD+. Ultraviolet detection at approximately 260 nm can be used for purity checks when concentrations are sufficient. Nuclear magnetic resonance spectroscopy provides structural confirmation and can distinguish anomeric forms.
| 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 |
In the salvage pathway, NMN is generated from nicotinamide and 5-phosphoribosyl-1-pyrophosphate by the enzyme nicotinamide phosphoribosyltransferase. A second route produces NMN from nicotinamide riboside through phosphorylation by nicotinamide riboside kinases. NMN is then converted to NAD+ by nicotinamide mononucleotide adenylyltransferases, often called NMNAT enzymes. This stepwise route allows cells to recycle nicotinamide and maintain NAD+ levels under changing metabolic conditions. The relative contribution of each route varies by tissue, species, and physiological state, and it remains an active area of research.
Research on NMN has expanded because NAD+ concentrations decline with age in some tissues and because NAD+ participates in energy metabolism, DNA repair, and signaling. Animal studies have reported changes in NAD+ levels after NMN administration, but human data are more limited and often focus on safety, pharmacokinetics, and biomarker changes. Questions remain about oral absorption, tissue distribution, and whether changes in blood NAD+ reflect changes inside specific organs. NMN is not an approved drug, and claims about its clinical effects should be distinguished from established biochemical findings.
Quality control for NMN focuses on identity, purity, residual solvents, heavy metals, and microbial limits. Because the molecule can absorb water, moisture content and packaging are relevant to shelf life. Suppliers may provide certificates of analysis, but independent verification is often needed for research or commercial use. The long-term stability of different crystal forms, salt forms, and formulations is not fully characterized in the public literature. Some degradation products and their effects on product performance remain open questions.
As a commercial ingredient, nicotinamide mononucleotide is commonly supplied as a powder or capsule. Its stability depends on temperature, moisture, pH, and light exposure. Hydrolytic and thermal degradation can increase over time, so manufacturers and laboratories often store material cold and dry. Purity is typically assessed with chromatographic methods, and identity can be confirmed by mass spectrometry. Published stability data for specific finished products remain limited. More data would help define shelf life under real-world conditions.
The biologically relevant form of NMN is generally the beta anomer, which is recognized by NMN adenylyltransferases. NMN is polar and water soluble, and it does not readily diffuse across lipid membranes without assistance. Whether intact NMN enters cells through a specific transporter remains an open question; some studies propose solute carrier family members, while other work favors extracellular dephosphorylation to nicotinamide riboside followed by uptake. This transport and compartmentalization debate affects how researchers interpret oral administration studies. The distinction between intracellular synthesis and extracellular delivery is central to current discussion.
Terminology around NMN can be confusing because several related compounds share the vitamin B3 family. Nicotinamide riboside is a nucleoside, whereas NMN is a nucleotide with a phosphate group, and NAD+ is a dinucleotide coenzyme rather than a simple precursor. Niacin and nicotinamide are also NAD+ precursors but follow different metabolic entry points. In commercial and scientific writing, NMN usually refers to beta-nicotinamide mononucleotide unless another form is specified. Consistent nomenclature helps distinguish chemical identity from proposed biological effects.
The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry", and work during this period progressed quickly. Like other androsteroids, testosterone is manufactured industrially from microbial fermentation of plant cholesterol (e.g., from soybean oil). In the early 2000s, the steroid market weighed around one million tonnes and was worth $10 billion, making it the 2nd largest biopharmaceutical market behind antibiotics.
=== CAM2038 - drug addiction === CAM2038 represents a new treatment concept for opiate addiction based on the well-documented anti-addiction therapeutic buprenorphine. CAM2038 is developed as a sustained release injection depot.
Automated synthesis or automatic synthesis is a set of techniques that use robotic equipment to perform chemical synthesis using a robotic system run using software control. Automating processes allows for higher efficiency and product quality although automation technology can be cost-prohibitive and there are concerns regarding overdependence and job displacement. Chemical processes were automated throughout the 19th and 20th centuries, with major developments happening in the previous thirty years, as technology advanced. Tasks that are performed may include: synthesis in variety of different conditions, sample preparation, purification, and extractions. Applications of automated synthesis are found on research and industrial scales in a wide variety of fields including polymers, personal care, and radiosynthesis.
The egg case genera Palaeoxyris and Fayolia, which are thought to have been produced by hybodonts and xenacanths respectively, two groups of extinct shark-like cartilaginous fish more closely related to modern sharks and rays than to chimaeras, resemble those of bulldog sharks in having a spiral collarettes running around them. Both Palaeoxyris and Fayolia taper towards their ends (with the tapering being more pronounced in Palaeoxyris), with one end having a tendril. Unlike modern sharks, these eggs are typically found in freshwater environments.
==== Tolerance ==== Tolerance and dependence are risks of chronic benzodiazepine use, and can result in doses within the therapeutic range ceasing to offer meaningful symptomatic relief after prolonged use. Tolerance develops at different rates and to different degrees to the sedative, hypnotic, anticonvulsant, muscle relaxant, and anxiolytic effects of benzodiazepines. A review of benzodiazepine tolerance concluded that it "appears that tolerance develops relatively quickly for the sedative and anticonvulsant actions of benzodiazepines, whereas tolerance to anxiolytic and amnesic effects probably does not develop at all", although the included randomized controlled trial evidence is limited to 22 weeks. A review of clonazepam in the treatment of psychiatric disorders concluded that longitudinal data supports anxiolytic benefit without tolerance during long-term use, including an open-label study finding continued benefit at three years. However, the review concludes that long-term RCT evidence is scant. A study of benzodiazepine sensitivity found that patients treated chronically with alprazolam did not differ from untreated patients in terms of anxiolytic response to diazepam, suggesting a lack of anxiolytic tolerance. However, controversy remains regarding tolerance to anxiolytic effects, with some publications reporting that there is little evidence of continued efficacy beyond 4–6 months or that dependence phenomena are common.
Sources: en.wikipedia.org
6 May – Terence Etherton, Baron Etherton, 73, British judge and politician, Master of the Rolls (2016–2021), chancellor of the High Court (2013–2016), and member of the House of Lords (since 2021). 20 May – Patrick O'Flynn, 59, British journalist (Daily Express) and politician, MEP (2014–2019), cancer. (death announced on this date) 13 June – Seán Neeson, 79, Northern Irish politician, MLA (1982–1986, 1998–2011). 1 July – David Lipsey, Baron Lipsey, 77, British journalist and life peer (since 1999). 7 July – Norman Tebbit, Baron Tebbit, 94, British politician, secretary of state for employment (1981–1983), chancellor of the Duchy of Lancaster (1985–1987), and MP (1970–1992). 9 July – Ian Blair, Baron Blair of Boughton, 72, British police officer and life peer, Commissioner of Police of the Metropolis (2005–2008), member of the House of Lords (since 2010). 13 July – Mark Schreiber, Baron Marlesford, 93, British politician, member of the House of Lords (since 1991). 17 July – Tommy Gallagher, 82, Northern Irish politician, MLA (1998–2011). (death announced on this date) 18 July – David Alliance, Baron Alliance, 93, Iranian-born British businessman, member of the House of Lords (2004–2025). 22 July – Sir Jamie McGrigor, 6th Baronet, 75, Scottish politician, MSP (1999–2016). (death announced on this date) 29 July – Meghnad Desai, Baron Desai, 85, Indian-born British economist and politician, member of the House of Lords (since 1991). 3 August – Stella Rimington, 90, British author and Director General of MI5 (1992–1996).
=== Sensory transduction === Pacinian corpuscles sense stimuli due to the deformation of their lamellae in the capsule and inner core, which in turn press on the membrane (axolemma) of the sensory neuron and causes it to bend or stretch. The external stimulus (deformation of or force on the external surface of the capsule) reaches axolemma of the terminal neurite through a complex mechanical filtration process. The internal lamellar spacing, number of lamella present in the capsule and the biomechanical properties of lamellae and the interlamellar fluid governs the characteristics of this mechanical filter acting on the external stimulus. When the axolemma are deformed by the filtered stumulus, due to either application or release of the external stimulus, a generator or receptor potential is created as it physically deforms the plasma membrane of axon terminal, making it "leak" different cations through mechanosensitive channels which initiates the receptor potential. This initial receptor potential is potentiated by voltage-activated ion channels present in the inner-core of the corpuscle. Finally, the receptor potential is modulated to neural spikes or action potential with the help of opening of sodium ion channels present at the first Ranvier's Node of the axon. Due to generation of receptor potential in the receptive area of the neurite (especially near the heminode or half-node of the axon) the potential at the first Ranvier's node can reach certain threshold, triggering nerve impulses or action potentials at the first node of Ranvier.
=== Relocation to Arkansas === With filming still underway in Mississippi, reports emerged that Lieutenant Governor Brad Dye was about to renege on Governor Mabus' permission to stage the finale at Jackson's State Capitol. Various reasons were mooted, ranging from the removal of a Magnolia tree (which would actually have been replanted afterwards), to graphic violence unbecoming of the institution, to potential damage to the building's antique windows. However, insiders posited that it was in fact retaliation against Mabus from within his own party, for allowing filming without consulting his Lieutenant Governor and House Speaker Tim Ford, who both had a legal say in the matter. Democratic state representatives Scott Ross and Robert Moak filed a motion to block the shoot, with Ross arguing that "[a]ny film whose major star is Brian Bosworth is grade-B at best and would do nothing to enhance the image of the state." While Ben Ami had successfully applied to use Jackson's Hinds County Courthouse as a fallback option, he instead announced on August 4 that his crew would relocate to Arkansas, whose Secretary of State Bill McCuen chided his neighbors for their risk aversion. Dye penned a letter to trade magazine Variety to justify his stance, and made a token offer to reinstate the shoot if displays of violence were cut, to which the filmmakers did not bother responding. Mississippi Film Commission boss Phil Cole resigned over the incident. Filming in Arkansas took place in Conway and Little Rock.
== Further reading == Kremyanskaya M, Ginzburg YZ, Hoffman R (March 2026). "Modulators of the hepcidin pathway in polycythemia vera and myelofibrosis". Blood. 147 (12): 1278–1288. doi:10.1182/blood.2025028643. PMID 41100735.
Sources: en.wikipedia.org
=== Democratic Leftwing Republican Party === In July 1925, a group of left-wing members of the Democratic Party joined the opposition and voted in favour of a motion of no confidence in António Maria da Silva's government. They were subsequently forced to resign from the Democratic Party and went on to form their own party, the Democratic Leftwing Republican Party.
=== Redox === Graphene oxide can be reversibly reduced and oxidized via electrical stimulus. Controlled reduction and oxidation in two-terminal devices containing multilayer graphene oxide films are shown to result in switching between partly reduced graphene oxide and graphene, a process that modifies electronic and optical properties. Oxidation and reduction are related to resistive switching.
=== June === 8 June – Police in Roraima rescue 108 Cuban migrants attempting to enter the country from Guyana and arrest five suspected human traffickers. 11 June–19 July – Brazil participates at the 2026 FIFA World Cup 13 June – A 21-year-old woman dies after two rope jumping instructors throw her from a bridge in Limeira without harnessing her to safety equipment. 14 June – Six people, including American musician Oliver Tree, are killed when two helicopters collide over Rio de Janeiro. 16 June – The Supreme Federal Court sentences Eduardo Bolsonaro to four years and two months' imprisonment for trying to involve the United States in the trial of his father, former president Jair Bolsonaro, over the 2022–2023 Brazilian coup plot. Twenty-five people, including 18 Venezuelan nationals, are arrested in Roraima as part of an operation against the Tren de Aragua.
In terms of reaction mechanism, SeO2 and the allylic substrate react via pericyclic process beginning with an ene reaction that activates the C−H bond. The second step is a [2,3] sigmatropic reaction. Oxidations involving selenium dioxide are often carried out with catalytic amounts of the selenium compound and in presence of a sacrificial catalyst or co-oxidant such as hydrogen peroxide. SeO2-based oxidations sometimes afford carbonyl compounds such as ketones, β-Pinene and cyclohexanone oxidation to 1,2-cyclohexanedione. Oxidation of ketones having α-methylene groups affords diketones. This type of oxidation with selenium oxide is called Riley oxidation. Aza analogues attach an amide, rather than alcohol, at the corresponding position (Ts=Tosyl):
==== Metabolism ==== Pseudoephedrine is not extensively metabolized and is subjected to minimal first-pass metabolism with oral administration. Due to its methyl group at the α carbon (i.e., it is an amphetamine), pseudoephedrine is not a substrate for monoamine oxidase (MAO) and is not metabolized by this enzyme. It is also not metabolized by catechol O-methyltransferase (COMT). Pseudoephedrine is demethylated into the metabolite norpseudoephedrine to a small extent. Similarly to pseudoephedrine, this metabolite is active and shows amphetamine-like effects. Approximately 1 to 6% of pseudoephedrine is metabolized in the liver via N-demethylation to form norpseudoephedrine.
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.
Common methods include HPLC with ultraviolet detection and LC-MS/MS. These techniques separate NMN from related nucleotides and quantify it by retention time and mass-to-charge ratio.