If you have been reading about Lyophilized powder and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-08-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Research on NAD+ spans biochemistry, aging biology, and metabolism. Studies often examine how NAD+ levels change with age, diet, exercise, or disease states, and whether precursor supplementation alters those levels. Findings in animal models do not automatically translate to humans, and measurement methods vary across studies. Questions about tissue-specific effects, long-term consequences, and causal relationships remain open. NAD+ itself is not established as a single therapeutic agent with a broad clinical role.
NAD+ stands for nicotinamide adenine dinucleotide, the oxidized form of a coenzyme found in all living cells. The molecule consists of two nucleotides, adenine and nicotinamide ribose, joined through phosphate groups. Its chemical formula is C21H27N7O14P2, and the free acid has a molar mass near 663.43 grams per mole. In redox reactions, NAD+ accepts a hydride ion and becomes NADH. The pair NAD+ and NADH participates in hundreds of metabolic reactions, including steps in glycolysis, the citric acid cycle, and oxidative phosphorylation.
In cells, NAD+ functions primarily as an electron carrier. Dehydrogenase enzymes in glycolysis and the citric acid cycle transfer hydride from substrates to NAD+, producing NADH. NADH then delivers electrons to the mitochondrial respiratory chain, supporting ATP synthesis. In fermentation, NADH is reoxidized to NAD+ so that glycolysis can continue. The balance between NAD+ and NADH helps set metabolic flux. Beyond redox, NAD+ serves as a substrate for enzymes that cleave it, including sirtuins, poly(ADP-ribose) polymerases, and CD38. These reactions consume NAD+ and release nicotinamide and ADP-ribose products.
Biosynthesis occurs through salvage, Preiss-Handler, and de novo pathways. In mammals, the salvage pathway from nicotinamide predominates, and NAMPT is often described as rate-limiting. Nicotinamide riboside and nicotinic acid enter related routes that converge on NAD+ production. Tissue NAD+ concentrations vary widely and are maintained by a balance of synthesis and consumption. Some studies report age-related declines in certain tissues, but whether these changes cause disease or can be reversed to improve human health remains an open question.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C21H27N7O14P2 | Free acid form; salt and hydrate forms differ in mass. |
| Molar mass | 663.43 g/mol | Anhydrous free acid; counterions and water change the value. |
| Appearance | White to off-white powder | Typical solid reagent; exact color varies by purity and form. |
| Solubility class | Highly water-soluble | Aqueous solutions are acidic; organic solubility is generally limited. |
| Common synonyms | DPN, coenzyme I, NAD | Older literature often uses diphosphopyridine nucleotide or DPN. |
Quantification of NAD+ in biological samples typically uses liquid chromatography coupled to mass spectrometry. Enzymatic cycling assays offer higher throughput and rely on NAD+ dependent dehydrogenases to amplify signal. Both approaches require careful sample quenching because NAD+ can be rapidly consumed or converted after collection. Acidic extraction is common for NAD+, while alkaline conditions favor NADH in some protocols. Isotopically labeled internal standards help correct for losses during extraction and ionization.
Commercial NAD+ is available at research grade, often with purity specifications determined by high-performance liquid chromatography. Certificates of analysis may report water content, residual solvents, and counterion identity. Identity can be confirmed by ultraviolet absorbance near 260 nm, mass spectrometry, or enzymatic activity. Because different salt forms and hydration states exist, researchers should verify that the product matches the intended molecular form. Lot-to-lot variation in purity can affect quantitative assays and should be documented.
Solid NAD+ is usually supplied as a white to off-white powder or lyophilized preparation. It is hygroscopic and should be kept desiccated at low temperature, commonly -20 °C or below for long-term storage. Aqueous solutions are less stable than dry material and are often prepared fresh or stored frozen in aliquots. Light exposure and repeated freeze-thaw cycles can promote degradation, so amber containers and single-use aliquots are preferred. Buffered solutions near neutral pH are generally less stable than acidic or frozen preparations.
Cells produce NAD+ through several biosynthetic routes. The salvage pathway recycles nicotinamide, while the Preiss-Handler pathway uses nicotinic acid, and a de novo route can start from tryptophan in some organisms. In mammals, the salvage pathway is generally considered the main source under ordinary conditions. Tissue concentrations vary widely by cell type and compartment, and measured declines with age have been reported in some studies. Whether such changes drive aging or mainly accompany it remains an open question.
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.
=== Cellular role === Hydrogen peroxide is a harmful byproduct of many normal metabolic processes; to prevent damage to cells and tissues, it must be quickly converted into other, less dangerous substances. To this end, catalase is frequently used by cells to rapidly catalyze the decomposition of hydrogen peroxide into less-reactive gaseous oxygen and water molecules. Mice genetically engineered to lack catalase are initially phenotypically normal. However, catalase deficiency in mice may increase the likelihood of developing obesity, fatty liver, and type 2 diabetes. Some humans have very low levels of catalase (acatalasia), yet show few ill effects. The increased oxidative stress that occurs with aging in mice is alleviated by over-expression of catalase. Over-expressing mice do not exhibit the age-associated loss of spermatozoa, testicular germ and Sertoli cells seen in wild-type mice. Oxidative stress in wild-type mice ordinarily induces oxidative DNA damage (measured as 8-oxodG) in sperm with aging, but these damages are significantly reduced in aged catalase over-expressing mice. Furthermore, these over-expressing mice show no decrease in age-dependent number of pups per litter. Overexpression of catalase targeted to mitochondria extends the lifespan of mice. In eukaryotes, catalase is usually located in a cellular organelle called the peroxisome. Peroxisomes in plant cells are involved in photorespiration (the use of oxygen and production of carbon dioxide) and symbiotic nitrogen fixation (the breaking apart of diatomic nitrogen (N2) to reactive nitrogen atoms).
Botany originated as herbalism, the study and use of plants for their possible medicinal properties. The early recorded history of botany includes many ancient writings and plant classifications. Examples of early botanical works have been found in ancient texts from India dating back to before 1100 BCE, Ancient Egypt, in archaic Avestan writings, and in works from China purportedly from before 221 BCE. Modern botany traces its roots back to Ancient Greece specifically to Theophrastus (c. 371–287 BCE), a student of Aristotle who invented and described many of its principles and is widely regarded in the scientific community as the "Father of Botany". His major works, Enquiry into Plants and On the Causes of Plants, constitute the most important contributions to botanical science until the Middle Ages, almost seventeen centuries later. Another work from Ancient Greece that made an early impact on botany is De materia medica, a five-volume encyclopaedia about preliminary herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides. De materia medica was widely read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya's Nabatean Agriculture, Abū Ḥanīfa Dīnawarī's (828–896) the Book of Plants, and Ibn Bassal's The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, and Ibn al-Baitar (d. 1248) wrote on botany in a systematic and scientific manner. In the mid-16th century, botanical gardens were founded in a number of Italian universities.
== Personal life == Hird married Tania Poynton on 11 October 1997. Around the time of the marriage, Poynton was working as a lawyer at legal firm Corrs Chambers Westgarth, where she remained until 2002. The couple have since separated. Hird shares four children with Tania: a daughter and three sons. One of his sons, Thomas Hird, was signed as a category B rookie at Essendon in 2019 and was delisted by Essendon in 2022. Tom Hird now plays for the Port Melbourne Football Club in the Victorian Football League. Hird's paternal grandfather, the late Allan Hird, Sr., was a notable player for and president of the Essendon Football Club, and his father, Allan Hird, Jr., had a brief playing career with Essendon. Hird completed a bachelor's degree in civil engineering in 1998 and worked in that capacity as a consultant on the CityLink project. He has also spent time working for a stockbroking firm and is an active partner in Gemba, a sports marketing and media consultancy firm based in Melbourne. He is the founder and managing director of Euree Asset Management, where he currently works. On 5 January 2017, Hird was taken to a private hospital following a drug overdose and suspected suicide attempt and was subsequently transferred to a specialist mental health care facility for further care and treatment. On 28 November 2018, Hird was hit by a car when cycling in Richmond.
Sources: en.wikipedia.org
== Production == Natural menthol is obtained by freezing peppermint oil. The resultant crystals of menthol are then separated by filtration. Total world production of menthol in 1998 was 12,000 tonnes of which 2,500 tonnes was synthetic. In 2005, the annual production of synthetic menthol was almost double. Prices are in the $10–20/kg range with peaks in the $40/kg region but have reached as high as $100/kg. In 1985, it was estimated that China produced most of the world's supply of natural menthol, although it appears that India has pushed China into second place. Menthol is manufactured as a single enantiomer (94% e.e.) on the scale of 3,000 tonnes per year by Takasago International Corporation. The process involves an asymmetric synthesis developed by a team led by Ryōji Noyori, who won the 2001 Nobel Prize for Chemistry in recognition of his work on this process:
=== Porosity of aerogel === There are several ways to determine the porosity of aerogel: the three main methods are gas adsorption, mercury porosimetry, and scattering method. In gas adsorption, nitrogen at its boiling point is adsorbed into the aerogel sample. The gas being adsorbed is dependent on the size of the pores within the sample and on the partial pressure of the gas relative to its saturation pressure. The volume of the gas adsorbed is measured by using the Brunauer, Emmit and Teller formula (BET), which gives the specific surface area of the sample. At high partial pressure in the adsorption/desorption the Kelvin equation gives the pore size distribution of the sample. In mercury porosimetry, the mercury is forced into the aerogel porous system to determine the pores' size, but this method is highly inefficient since the solid frame of aerogel will collapse from the high compressive force. The scattering method involves the angle-dependent deflection of radiation within the aerogel sample. The sample can be solid particles or pores. The radiation goes into the material and determines the fractal geometry of the aerogel pore network. The best radiation wavelengths to use are X-rays and neutrons. Aerogel is also an open porous network: the difference between an open porous network and a closed porous network is that in the open network, gases can enter and leave the substance without any limitation, while a closed porous network traps the gases within the material forcing them to stay within the pores.
=== Regulation === Acetyl-CoA is formed into malonyl-CoA by acetyl-CoA carboxylase, at which point malonyl-CoA is destined to feed into the fatty acid synthesis pathway. Acetyl-CoA carboxylase is the point of regulation in saturated straight-chain fatty acid synthesis, and is subject to both phosphorylation and allosteric regulation. Regulation by phosphorylation occurs mostly in mammals, while allosteric regulation occurs in most organisms. Allosteric control occurs as feedback inhibition by palmitoyl-CoA and activation by citrate. When there are high levels of palmitoyl-CoA, the final product of saturated fatty acid synthesis, it allosterically inactivates acetyl-CoA carboxylase to prevent a build-up of fatty acids in cells. Citrate acts to activate acetyl-CoA carboxylase under high levels, because high levels indicate that there is enough acetyl-CoA to feed into the Krebs cycle and conserve energy. High plasma levels of insulin in the blood plasma (e.g. after meals) cause the dephosphorylation of acetyl-CoA carboxylase, thus promoting the formation of malonyl-CoA from acetyl-CoA, and consequently the conversion of carbohydrates into fatty acids, while epinephrine and glucagon (released into the blood during starvation and exercise) cause the phosphorylation of this enzyme, inhibiting lipogenesis in favor of fatty acid oxidation via beta-oxidation.
=== Board members and trustees === On January 5, 2017, the board of trustees announced the selection of Rajiv Shah to serve as the 13th president of the foundation. Shah became the youngest person, at 43, and first Indian-American to serve as president of the foundation. He assumed the position March 1, succeeding Judith Rodin who served as president for nearly twelve years and announced her retirement, at age 71, in June 2016. A former president of the University of Pennsylvania, Rodin was the first woman to head the foundation. Rodin in turn had succeeded Gordon Conway in 2005. Current staff as of June 1, 2021 include:
Sources: en.wikipedia.org
Healthcare in Romania is mainly provided by the public sector, which runs most hospitals and offers national health insurance to nearly all citizens. In 2021, healthcare costs were US$16. 7 billion, or US$2,385 per person, making up €5.69 of GDP. Government spending is higher than in markets like Bulgaria but lower than Hungary. Spending is expected to rise by 7. US$5 billion (+37. 68%) from 2024 to 2028, reaching 27. US$3 billion by 2028. The Romanian National Institute of Statistics reports over 65,000 health units in Romania, with 53,000 in urban areas and 12,000 in rural areas. There are 543 hospitals, including 488 in urban and 55 in rural areas, along with 160 other hospital-like establishments. Nearly 50% of these are large facilities with over 100 beds, while 39% are small with fewer than 50 beds. The total number of inpatient beds is 135,085, allocated mainly to psychiatry, surgery, and internal medicine among other specialties.
== See also == Butyric acid α-Aminobutyric acid (homoalanine) 2-Hydroxybutyric acid (α-hydroxybutyric acid) Other oxobutanoic acids 3-Oxobutanoic acid (acetoacetic acid) 4-Oxobutanoic acid (succinic semialdehyde)
Transportation in Colombia is regulated within the functions of the Ministry of Transport and entities such as the National Roads Institute (INVÍAS) responsible for the Highways in Colombia, the Aerocivil, responsible for civil aviation and airports, the National Infrastructure Agency, in charge of concessions through public–private partnerships, for the design, construction, maintenance, operation, and administration of the transport infrastructure, the General Maritime Directorate (Dimar) has the responsibility of coordinating maritime traffic control along with the Colombian Navy, among others, and under the supervision of the Superintendency of Ports and Transport. In 2021, Colombia had 204,389 km (127,001 mi) of roads, 32,280 km (20,058 mi) of which were paved. At the end of 2017, the country had around 2,100 km (1,305 mi) of duplicated highways. Rail transportation in Colombia is dedicated almost entirely to freight shipments and the railway network has a length of 1,700 km of potentially active rails. Colombia has 3,960 kilometers of gas pipelines, 4,900 kilometers of oil pipelines, and 2,990 kilometers of refined-products pipelines. The Colombian government aimed to build 7,000 km of roads between 2016 and 2020, which would reduce travel times by an estimated 30 per cent, and transport costs by an estimated 20 per cent.
27 March – A report clears Conservative MP Bernard Jenkin of breaching COVID-19 laws over his attendance at a "wine and nibbles" event on the Parliamentary estate in December 2020, which the report describes as socially-distanced with "business and social elements". 28 March – Keir Starmer and Angela Rayner launch Labour's campaign for the 2024 United Kingdom local elections at an event in Dudley. Honours are conferred on businessman and senior Conservative Party treasurer Mohamed Mansour, Farming Minister Mark Spencer and Shipley MP Philip Davies, all of who receive knighthoods, while former ministers Tracey Crouch and Harriett Baldwin are awarded damehoods. The announcement comes as part of an honours list published at the start of the Parliamentary recess. The Assisted Dying for Terminally Ill Adults (Scotland) Bill, a bill to legalise assisted dying in Scotland and drafted by Liberal Democrat MSP Liam McArthur, is introduced into the Scottish Parliament. 29 March – Sir Jeffrey Donaldson resigns as leader of the Democratic Unionist Party after being charged with rape and other historical sexual offences. Gavin Robinson is appointed interim leader until a new leader can be elected. 30 March – First Minister of Northern Ireland Michelle O'Neill says she is determined the Stormont Assembly and Executive will continue to function following the resignation of Jeffrey Donaldson as DUP leader. 31 March – The UK government says it will work alongside the Northern Ireland Executive to maintain stability at Stormont.
=== Chemistry === The chemistry of polonium is similar to that of tellurium, although it also shows some similarities to its neighbor bismuth due to its metallic character. Polonium dissolves readily in dilute acids but is only slightly soluble in alkalis. Polonium solutions are first colored in pink by the Po2+ ions, but then rapidly become yellow because alpha radiation from polonium ionizes the solvent and converts Po2+ into Po4+. As polonium also emits alpha-particles after disintegration, this process is accompanied by bubbling and emission of heat and light by glassware due to the absorbed alpha particles; as a result, polonium solutions are volatile and will evaporate within days unless sealed. At pH about 1, polonium ions are readily hydrolyzed and complexed by acids such as oxalic acid, citric acid, and tartaric acid.
Sources: en.wikipedia.org
NAD+ is a coenzyme found in all living cells. It carries electrons in metabolic reactions and also serves as a substrate for enzymes involved in signaling and DNA repair. Its oxidized and reduced forms are central to energy metabolism.
NAD+ is the oxidized form and NADH is the reduced form. The pair accepts and donates electrons in redox reactions. Their ratio helps indicate the metabolic state of a cell or compartment.
No. Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are precursors that cells can convert into NAD+. They are distinct molecules with different absorption and metabolism profiles.
Nicotinamide adenine dinucleotide, with the plus sign indicating the oxidized form. It is a coenzyme present in all living cells. The reduced form is NADH.