Redox coenzyme 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.
Updated 2026-06-11. Numbers and descriptions here follow the published literature rather than marketing material.
NAD+ is a dinucleotide composed of adenine, ribose, and nicotinamide moieties linked by phosphate groups. Its oxidized form carries a positive charge on the nicotinamide ring, which enables reversible hydride transfer. The molecule functions as a coenzyme in oxidoreductase reactions rather than as a dietary vitamin in its intact form. Cells maintain separate pools in cytoplasm, mitochondria, and nucleus. This compartmentalization allows distinct redox environments while preserving a shared chemical identity.
In glycolysis, NAD+ accepts electrons during the oxidation of glyceraldehyde-3-phosphate, forming NADH. The tricarboxylic acid cycle and fatty acid oxidation also generate NADH, which donates electrons to the mitochondrial electron transport chain. This flow supports ATP synthesis and helps maintain the redox balance of the cell. Other dehydrogenases use NAD+ as a cofactor for biosynthetic reductions and detoxification reactions. NADH is later reoxidized to sustain continued flux through these pathways.
Beyond electron transfer, NAD+ serves as a substrate for enzymes that cleave the molecule and transfer ADP-ribose units. Sirtuins, poly(ADP-ribose) polymerases, and CD38 consume NAD+ in regulatory reactions. These activities link NAD+ availability to DNA repair, chromatin modification, calcium signaling, and metabolic stress responses. Because consumption can exceed biosynthesis under some conditions, cellular NAD+ levels are dynamic rather than fixed. Enzyme affinity and local synthesis also influence how much NAD+ is available for signaling.
NAD+ is a dinucleotide composed of adenine, ribose, and nicotinamide groups joined by phosphate linkages. It serves as a coenzyme in oxidoreductase reactions, cycling between oxidized NAD+ and reduced NADH. The molecule is water-soluble and occurs in all living cells. Its nicotinamide ring accepts hydride ions during catabolic reactions, linking substrate oxidation to electron transport. This redox couple supports ATP production and helps maintain cytosolic and mitochondrial redox balance in many cell types.
Beyond redox catalysis, NAD+ is a substrate for enzymes that transfer ADP-ribose or remove acetyl groups from proteins. Sirtuins and poly(ADP-ribose) polymerases consume NAD+ and release nicotinamide as a byproduct. These reactions connect cellular energy status to gene regulation, DNA repair, and stress responses. Because NAD+ is used rather than merely recycled in such signaling, its concentration reflects both biosynthesis and consumption. The balance between salvage and de novo synthesis pathways determines available pools in different tissues.
Biosynthesis of NAD+ starts from nicotinamide, nicotinic acid, or nicotinamide riboside through salvage pathways. A rate-limiting enzyme, nicotinamide phosphoribosyltransferase, converts nicotinamide to nicotinamide mononucleotide. Further coupling with ATP yields NAD+. In mammals, the liver and muscle can synthesize NAD+ from dietary precursors, but tissue levels vary widely. Researchers study these pathways to understand age-related changes, metabolic disorders, and neurodegeneration. Direct causal links between NAD+ decline and disease remain an active area of investigation.
| Property | Value | Notes |
|---|---|---|
| Chemical name | Nicotinamide adenine dinucleotide | Oxidized form abbreviated NAD+ |
| Molecular formula | C21H27N7O14P2 | Free acid form |
| Molar mass | 663.43 g/mol | Calculated for free acid |
| CAS Registry Number | 53-84-9 | Common entry for beta-NAD+ |
| Appearance | White to off-white powder | Hygroscopic solid |
In aqueous solution, NAD+ is most stable under mildly acidic to neutral conditions and degrades faster at high pH or elevated temperature. The molecule can hydrolyze at the pyrophosphate bond or undergo nonenzymatic cyclization. Buffers, chelating agents, and cold temperatures slow these losses during analysis. Repeated freeze-thaw cycles are generally avoided because they can promote degradation and concentration changes. Light exposure is also controlled, though NAD+ is less photolabile than some related nucleotides.
Commercial NAD+ is supplied as a solid, often as the free acid or a salt, and purity is verified by chromatographic methods. Laboratories typically store it desiccated at minus 20 degrees Celsius or below. Working solutions are prepared fresh because even sterile aqueous solutions can lose activity over hours to days depending on pH and temperature. Documentation may include a certificate of analysis, an assay value, and a recommended retest date. Researchers should verify identity and purity when results depend on precise cofactor concentrations.
Quality control for NAD+ relies on identity, purity, and functional tests. A certificate of analysis may report high-performance liquid chromatography purity, ultraviolet spectrum, water content, and residual solvents. Because NAD+ is hygroscopic, gravimetric values can shift as material absorbs water, so purity should be interpreted alongside storage history. Mass spectrometry confirms molecular identity, while enzymatic assays show whether the material supports dehydrogenase activity. Commercial material is available as the free acid and as salts, and the counterion affects molecular weight, solubility, and how concentrations are calculated.
Laboratory measurement of NAD+ usually begins with rapid sample quenching because the molecule can change form after collection. Enzymatic cycling assays amplify signal through coupled reactions and are suited to small samples. High-performance liquid chromatography with ultraviolet detection separates NAD+ from related nucleotides. Liquid chromatography-mass spectrometry offers higher specificity and can distinguish NAD+ from close analogs. Each method has trade-offs in sensitivity, throughput, and equipment needs, so reported values depend heavily on extraction and detection choices.
Stability of NAD+ depends on form, temperature, pH, and water content. The solid is generally more stable than solutions, and it should be kept dry and cold. In solution, hydrolysis can cleave the dinucleotide, especially under alkaline conditions or at elevated temperature. Light exposure may also contribute to degradation. Buffers, chelating agents, and sterile handling can reduce losses, but no single condition preserves all preparations indefinitely. Researchers often prepare working solutions shortly before use and verify activity or purity after storage.
== Fungi foods == Dried mushrooms – typically prepared by sun-drying, hot-air drying or freeze-drying. Some types of mushrooms that are prepared dried include shiitake, straw and morel mushrooms. Mushroom extract – a paste-like, concentrated extract made from dried edible mushrooms. Mushroom extract is used to add flavor to soups, sauces, soy sauce and other foods.
=== Tunable vacuum ultraviolet (VUV) === The vacuum ultraviolet (V‑UV) band (100–200 nm) can be generated by non-linear 4 wave mixing in gases by sum or difference frequency mixing of 2 or more longer wavelength lasers. The generation is generally done in gasses (e.g. krypton, hydrogen which are two-photon resonant near 193 nm) or metal vapors (e.g. magnesium). By making one of the lasers tunable, the V‑UV can be tuned. If one of the lasers is resonant with a transition in the gas or vapor then the V‑UV production is intensified. However, resonances also generate wavelength dispersion, and thus the phase matching can limit the tunable range of the 4 wave mixing. Difference frequency mixing (i.e., f1 + f2 − f3) has an advantage over sum frequency mixing because the phase matching can provide greater tuning. In particular, difference frequency mixing two photons of an ArF (193 nm) excimer laser with a tunable visible or near IR laser in hydrogen or krypton provides resonantly enhanced tunable V‑UV covering from 100 nm to 200 nm. Practically, the lack of suitable gas / vapor cell window materials above the lithium fluoride cut-off wavelength limit the tuning range to longer than about 110 nm. Tunable V‑UV wavelengths down to 75 nm was achieved using window-free configurations.
An embalmer is someone who has been trained and qualified in the art and science of sanitization, presentation, and preservation of the human deceased. The term mortician is far more generic; it may refer to someone who is a funeral director, an embalmer, or just a person who prepares the deceased, with or without the formal qualification of an embalmer. Thus while all embalmers are morticians, many morticians are not embalmers and the terms are not intrinsically synonymous. Embalming training commonly involves formal study in anatomy, thanatology, chemistry, and specific embalming theory (to widely varied levels depending on the region of the world one lives in) combined with practical instruction in a mortuary with a resultant formal qualification granted after the passing of a final practical examination and acceptance into a recognized society of professional embalmers. The roles of a funeral director and embalmer are different, depending on local customs and the licensing body of the region in which they both operate. A funeral director arranges for the final disposition of the deceased, and may or may not prepare the deceased (by embalming, preparing for viewing or other legal requirements). Legal requirements over who can practice vary geographically. Some regions or countries do not have specific requirements, while others have clear prohibitions. In the United States, the title of an embalmer is largely based on the state in which they are licensed.
Sources: en.wikipedia.org
== Alternatives == In general, COBRA is often combined with other DNA methylation analyses and is frequently used in the initial screening of a loci of interest. If COBRA suggests altered methylation patterns, then more rigorous, labor-intensive techniques can be applied, such as bisulfite sequencing or MeDIP. Also PacBio sequencing can be used to detect DNA methylation.
Viral hemorrhagic fevers (VHFs) are a diverse group of infectious diseases characterized by fever and systemic damage to the circulatory system caused by RNA viruses. Viral hemorrhagic fevers cause symptoms ranging from mild to life-threatening, depending on the virus involved, but generally cause internal bleeding that leads to sudden onset of muscle pain, fever, and hypotension. In severe cases, it can cause life-threatening shock and bleeding from internal organs. While some VHFs are generally mild, such as nephropathia epidemica (caused by two species of hantavirus), many are debilitating or lethal without treatment. Outbreaks of VHFs tend to have high case fatality rates and disproportionately affect communities with poor health infrastructure. Therefore, the emergence of VHFs is a growing public health concern. VHFs are often zoonoses, meaning they can be transmitted from wild animals to human populations; for instance, the Lassa arenavirus is spread by mice. Viral hemorrhagic fevers are caused by members of seven families of single-stranded RNA viruses: Arenaviridae, Filoviridae, Flaviviridae, Nairoviridae, Phenuiviridae, Hantaviridae and Peribunyaviridae.
=== Third week (7–13 March) === On 7 March, Pakistani officials stated that they had carried out air strikes along the Pakistan-Afghanistan border, destroying several Afghan Taliban positions. The officials added the airstrikes inflicted heavy casualties on the Taliban forces, forcing them to abandon and flee from those positions. Meanwhile, Taliban officials said that Pakistani forces had bombed the provinces of Paktia, Paktika, Khost, Maidan Wardak, and Kunar, resulting in civilian casualties and damage to homes and shops. Taliban officials did not comment on the casualties suffered by their forces. Taliban officials also urged the United Nations Security Council (UNSC) to take action to stop Pakistan's attacks. They cited recent strikes on several Afghan provinces, civilian casualties, displacement, and the expulsion and harassment of Afghan refugees in Pakistan, and called on the UNSC to help end the situation. Taliban officials in Torkham border crossing area said that Pakistan's attacks have destroyed at least 150 shops, resulting heavy financial losses for Afghan business owners. In Nangarhar province, residents state that the Taliban had forced them to participate in a protest against Pakistan in Jalalabad, in some cases by offering cash payments. Three Policemen were killed and 31 people including five Policemen and 26 civilians were wounded in an IED attack targeting a police patrol in Wana. A drone attack on relatives of police peace committee killed two and wounded seven in Lakki Marwat District while a bomb blast killed two more civilians and wounded ten.
The clitoris develops from a phallic outgrowth in the embryo called the genital tubercle. In the absence of testosterone, the genital tubercle allows for the formation of the clitoris; the initially rapid growth of the phallus gradually slows and the body and glans of the clitoris are formed along with its other structures.
Sources: en.wikipedia.org
Sheikh Sāleḥ bin Fawzān bin ‘Abd Allāh al-Fawzān (born 28 September 1935) is a Saudi Islamic scholar who is the fourth and current Grand Mufti of Saudi Arabia, serving since 22 October 2025. He is regarded as one of the senior scholars within the Salafi movement. Al-Fawzan is also a member of Saudi Arabia's Council of Senior Scholars and the fiqh council in Mecca, affiliated with the Muslim World League. He also serves as a member of the Supervisory Committee for Preachers during Hajj, and a member of the Permanent Committee for Scholarly Research and Ifta in the Saudi Arabia. In addition to this, he is an imam, khatib and teacher at the Prince Mutaib bin Abdulaziz Al Saud Mosque in Riyadh. He participates in the radio program Nūr 'Alā al-Darb, answering questions on Islamic topics, and contributes to scholarly journals in the form of research, studies, letters, and fatwas.
Histology image: 07903loa – Histology Learning System at Boston University - "Eye: fovea, RPE" Histology image: 08103loa – Histology Learning System at Boston University - "Integument: pigmented skin" UMass Amherst Libraries (2016-04-29). 7. Pigment Transfer in Skin Cells. Retrieved 2026-05-20 – via YouTube.
=== Diplomatic relations === After the UDI, Rhodesia maintained several overseas missions, including Pretoria, and until 1975, Lisbon in Portugal and Lourenço Marques (now Maputo) in Mozambique. Since 1961, Rhodesia had an "Accredited Diplomatic Representative" with South Africa, heading a "Rhodesian Diplomatic Mission" or de facto embassy. Before South Africa left the Commonwealth that year, the then Southern Rhodesia had exchanged High Commissioners with the then Union of South Africa, but following the change in status, the Republic now had a "South African Diplomatic Mission" in Salisbury. During 1965, the government of Rhodesia made moves to establish a mission in Lisbon separate from the British Embassy, with its own accredited representative, having previously been able to establish its own consulate in Lourenço Marques, capital of Portuguese Mozambique. This prompted protests from the British government, which was determined that the representative, Harry Reedman, should be a nominal member of the British Ambassador's staff. For their part, the Portuguese authorities sought a compromise whereby they would accept Reedman as an independent representative but deny him diplomatic status. The Rhodesian Information Office in Washington remained open following UDI, but its director, Ken Towsey, and his staff were deprived of their diplomatic status. Previously, there had been a "Minister for Rhodesian Affairs" operating under the aegis of the British Embassy in Washington, as well representatives in Tokyo and Bonn.
==== MeSH D12.776.835.725.934 – prokaryotic initiation factors ==== MeSH D12.776.835.725.934.374 – prokaryotic initiation factor-1 MeSH D12.776.835.725.934.562 – prokaryotic initiation factor-2 MeSH D12.776.835.725.934.750 – prokaryotic initiation factor-3
==== Synthetic cannabinoids ==== Synthetic cannabinoids, members of the aminoalkylindole class, made its first appearance in 2008. It was given the name 'JWH' because a chemist called John W. Huffman synthesized them in the 1960s. Most synthetic analogs of cannabinoids mimic the structure of 9-tetrahydrocannabinol (THC), which makes them an agonist to the CB1(Type I) and CB2 (Type II) cannabinoid receptors. CB1 in particular, is expressed in the central nervous system and largely responsible for the psychoactive effect.. A typical agonist consists of the following components: head, linker core and tail. Altering the structure from each component will affect the drug's affinity to the cannabinoid receptors. For instance, when a fluoride or nitrile group is attached to the carbon chains, the affinity for CB1 will increase. The aromatic rings from the aminoalkylindole class also play the role of enhancing the affinity by forming a hydrophobic cavity to stabilize the CB1 receptors. As legislation becomes tightened under the monitoring of Early Warning System (EWS), attempts are made to alter the structure which produce new analogues such as the Cyclopropylindoles (UR-144) and adamantylindoles (APINACA).
Sources: en.wikipedia.org
NAD+ is the oxidized form, while NADH is the reduced form carrying an additional hydride equivalent. The pair participates in reversible electron transfer reactions. Their ratio helps indicate the redox state of a compartment.
NAD+ itself is not classified as a vitamin, but its precursor niacin is an essential nutrient in humans. Cells synthesize NAD+ from niacin, nicotinamide, nicotinamide riboside, or tryptophan. The intact dinucleotide is not obtained directly from typical diets in meaningful amounts.
Age-related studies often examine whether NAD+ levels decline in tissues and whether that decline affects mitochondrial function or DNA repair. Interventions using precursor molecules raise open questions about cause and effect. Current evidence does not establish that changing NAD+ levels slows human aging.
NAD+ is the oxidized form and NADH is the reduced form of the same coenzyme. NAD+ accepts electrons during oxidation reactions, becoming NADH, which can donate electrons in other reactions. The ratio between them helps describe a cell's redox state.