The short version of hydrolysis fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-10. Anything still debated is marked as such rather than presented as settled.
NAD+ is a dinucleotide composed of nicotinamide, ribose, and adenine linked by phosphate groups. Its full name is nicotinamide adenine dinucleotide, with "+" denoting the oxidized form. The molecule acts as a coenzyme in redox reactions, cycling between NAD+ and NADH. In cells, it participates in electron transfer during glycolysis, the citric acid cycle, and oxidative phosphorylation. It is distinct from NADP+, which carries an additional phosphate group and supports different biosynthetic reactions.
Beyond redox chemistry, NAD+ serves as a substrate for enzymes that transfer ADP-ribose or remove acetyl groups. Sirtuins, PARPs, and CD38-family enzymes consume NAD+ and produce nicotinamide and ADP-ribose-related products. These reactions link NAD+ availability to DNA repair, chromatin modification, and cellular signaling. Because the molecule is central to energy metabolism and regulation, changes in its concentration are studied in aging, immunity, and metabolic research. The balance between synthesis and consumption varies by tissue, developmental stage, and physiological state.
In humans, NAD+ can be synthesized from nicotinic acid, nicotinamide, nicotinamide riboside, and tryptophan through overlapping pathways. The salvage pathway recycles nicotinamide back to NAD+ and is often considered a major route in many tissues. Dietary precursors and intracellular recycling both contribute to the pool, but the quantitative importance of each source remains an active research question. NAD+ levels are not uniform across organs or cell compartments. Measurements in blood do not necessarily reflect concentrations inside tissues.
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a dinucleotide built from adenine, nicotinamide, two ribose sugars, and two phosphate groups. The oxidized form carries a positive charge on the nicotinamide ring, while the reduced form, NADH, is neutral. This pair acts as a reversible electron carrier in cells. NAD+ is present in bacteria, plants, animals, and fungi. Its structure allows it to accept and donate electrons without being consumed in the reactions it supports.
In redox reactions, NAD+ accepts a hydride ion, which consists of two electrons and one proton. The hydride adds to the nicotinamide ring at a specific carbon, converting NAD+ into NADH. Dehydrogenase enzymes use this step in glycolysis, the citric acid cycle, and fatty acid oxidation. NADH later donates electrons to the mitochondrial electron transport chain, helping to drive ATP synthesis. The balance between NAD+ and NADH reflects the metabolic state of a cell, and shifts in that balance can alter how pathways operate.
Beyond electron transfer, NAD+ serves as a substrate for enzymes that cleave it and attach its ADP-ribose portion to other molecules. This group includes poly(ADP-ribose) polymerases, CD38, and sirtuins. Such reactions consume NAD+ and can influence its availability for metabolism. Cells replenish NAD+ through a salvage pathway that recycles nicotinamide and through routes starting from tryptophan or vitamin B3 forms. How these synthesis and consumption routes are coordinated across tissues remains an active area of study, and compartment-specific concentrations are difficult to measure directly.
| Property | Value | Notes |
|---|---|---|
| Common name | Nicotinamide adenine dinucleotide (oxidized) | Often shortened to NAD+ |
| Chemical class | Dinucleotide | Contains nicotinamide and adenine moieties |
| Molecular formula | C21H27N7O14P2 | Free acid form; charge depends on pH |
| Molar mass | About 663.43 g/mol | Calculated for C21H27N7O14P2 |
| CAS number | 53-84-9 | Common identifier for beta-NAD+ |
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.
NAD+ also serves as a substrate for enzymes that cleave it, including sirtuins, PARPs, and CD38. These enzymes consume NAD+ and release nicotinamide and ADP-ribose or related products. The dual roles as redox cofactor and signaling substrate connect NAD+ to DNA repair, circadian regulation, and calcium signaling. Cellular NAD+ concentrations vary by tissue, time of day, and stress exposure. How these consumption pathways interact with redox balance remains an active area of research.
Measuring NAD+ in biological samples requires rapid processing because the compound can degrade or interconvert after collection. Common approaches include enzymatic cycling assays, high-performance liquid chromatography, and mass spectrometry. Each method has different sensitivity, specificity, and susceptibility to interference from related nucleotides. Sample type matters: cultured cells, animal tissues, and human blood present distinct challenges. Reported values can vary widely across laboratories because of differences in extraction, normalization, and analytical platform. Standardization remains an open issue in the field.
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.
=== Children === Its use in children is generally advised against, although it may be done under the supervision of a specialist. On 21 September 2015, the FDA started investigating the safety of tramadol in use in persons under the age of 17. The investigation was initiated because some of these people have experienced slowed or difficult breathing. The FDA lists age under 12 years old as a contraindication.
=== Politicians and administrators === Sir Abubakar Tafawa Balewa (Gere/Fulani) – Nigerian politician and the first prime minister of an independent Nigeria. Ahmadu Bello – Sardauna of Sokoto and first premier of Northern Region of Nigeria. Shehu Shagari – Turaki of Sokoto and the first elected president of Nigeria. Major-General Mohammadu Buhari – former president and former Head of State of Nigeria. Umaru Musa Yar'Adua – former president of Nigeria. Namadi Sambo - former vice president of Nigeria Aminu Kano – politician and teacher. Atiku Abubakar – former vice president of Nigeria. Muhammadu Abubakar Rimi – former governor of Kano State, politician. Rabiu Kwankwaso – former governor of Kano State, Nigeria, former minister of defence. Abdullahi Umar Ganduje – former governor of Kano State, Nigeria. Nasir Ahmad el-Rufai – former governor of Kaduna State, former minister of federal capital. Isa Yuguda - economist, former Minister of Aviation, former governor of Bauchi State. Abubakar Atiku Bagudu – former governor of Kebbi State, Senate Second Republic, Nigeria. Sule Lamido – former governor of Jigawa State, Nigeria, former minister of foreign affairs. Aliyu Magatakarda Wamakko – former governor of Sokoto State and current senator of Sokoto North. Danbaba Suntai - former governor Of Taraba State. Dikko Umar Radda - Governor of Katsina State. Gidado Idris – former secretary to the Government of The Federation. Muhammadu Dikko Yusufu - former Inspector General of Police.
He was only arrested in 2006 after he returned to Russia, believing that the ten-year old case was closed. Felshtinsky and Pribylovsky claimed that Russia's security services, which had access to the chemical agent, had framed Khutsishvili for the murder, and that the security services had organised the murder on the orders of a senior Russian state official. Boris Kuznetsov, who represented Khutsishvili and believed in his innocence, blames "rogue intelligence officers". Leonid Rink, an employee of GosNIIOKhT, received a one-year suspended sentence for selling Novichok agents to unnamed buyers "of Chechen ethnicity" soon after the poisoning of Kivelidi and Izmailova.
Sources: en.wikipedia.org
=== Opposition to the Peace Preservation Act === In 1878, the Cape Parliament had passed the Peace Preservation Act, which allowed for the confiscation of the firearms of the African population in exchange for a monetary compensation. Sprigg decided that its implementation should extend to the Basuto, after witnessing 7,000 Basuto cavalrymen perform maneuvers during the course of Moorosi's uprising. This was announced during a pitso (formal assembly) attended by some 6,000 to 10,000 Basuto. Soon afterwards he also declared that the Quthing region would be confiscated by the Cape for white settlement. At the time almost half of all Basuto men owned a firearm. Many had worked in railway construction and the diamond mines in Griqualand West with the express purpose of purchasing modern breech-loading and smoothbore rifles. As a result, the Basuto became the best-armed tribe in southern Africa. For the Basuto gun confiscation was unacceptable, not only due to their high value, but also due to the necessity to defend their land and cattle in an environment where there was no guarantee of protection from the colonial authorities. For the Basuto, guns were a symbol of manhood, and to be disarmed was seen as being reduced to the status of a child. In April 1879, the Cape Colony doubled the hut tax in Basutoland to one £ per hut. In June 1880, Letsie I dispatched a three-man delegation to the Cape Parliament as it was deliberating the annexation of Quthing and the question of Basuto disarmament.
These findings are based on decades of data, and control for cohort groups; the data avoids the risk that the drops in happiness during midlife are due to populations' unique midlife experiences, like a war. The studies have also controlled for income, job status and parenting (as opposed to childlessness) to try to isolate the effects of age. Researchers found support for the notion of age changes inside the individual that affect happiness. This could be for any number of reasons. Psychological factors could include greater awareness of one's self and preferences; an ability to control desires and have more realistic expectations – unrealistic expectations tend to foster unhappiness; moving closer to death may motivate people to pursue personal goals; improved social skills, like forgiveness, may take years to develop – the practice of forgiveness seems linked to higher levels of happiness; or happier people may live longer and are slightly overrepresented in the elderly population. Age-related chemical changes might also play a role. Other studies have found older individuals reported more health problems, but fewer problems overall. Young adults reported more anger, anxiety, depression, financial problems, troubled relationships and career stress. Researchers also suggest depression in the elderly is often due largely to passivity and inaction – they recommend people continue to undertake activities that bring happiness, even in old age.
Mammals such as lemurs and monkeys demonstrate application of chemicals similar to how humans use chemicals for pest management and medical use. These applications vary from prevention of internal and external parasites or pathogens, decrease likelihood of infection, increase reproductive function, reducing inflammation, social cues, and more. Red-fronted lemurs (Eulemur ruffrons) have evolved two pathways, preventive measure for avoiding bioaccumulation, allowing for the modification of 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone a secretion of Spirostreptidae millipedes shown to inhibit certain bacterial species. Red-fronted lemurs have also been observed in rubbing the secretion on their fur similar to capuchins, this action uses benzoquinone compounds as repellent for various insects such as ticks and mosquitoes.
Cardiovascular Bradycardia Bundle branch blocks Complete heart block and arrhythmias Cardiomegaly Elevated diastolic blood pressure—early Hypotension—late Low cardiac output Non-specific ECG findings Pericardial effusion Polymorphic ventricular tachycardia (torsades de pointes) Prolonged QT interval Respiratory Hypoxia Hypercapnia Hyperventilation Myxedema of the larynx Pleural effusion Gastrointestinal Abdominal distention Abdominal pain Anasarca Anorexia and nausea Decreased motility Fecal impaction and constipation Gastrointestinal atony or ileus Myxedema or toxic megacolon—late Neurogenic oropharyngeal dysphagia ileus Neurological Altered mentation Coma Confusion and obtundation Delayed tendon reflexes Depression Poor cognitive function Psychosis Seizures Renal and urinary function Bladder dystonia and distension Fluid retention Appearance and dermatological Alopecia Coarse, sparse hair Dry, cool, doughy skin Myxedematous face Generalized swelling Goiter Macroglossia Non-pitting edema Ptosis Periorbital edema Surgical scar from prior thyroidectomy Hypothermia (often marked: usually < 35 °C/ 95 °F) Laboratory features in myxedema coma:
Sources: en.wikipedia.org
The plus sign indicates the oxidized form of nicotinamide adenine dinucleotide, which can accept electrons. When it accepts electrons, it becomes NADH. The two forms together support redox reactions in cells.
No. NAD+ is the oxidized form and NADH is the reduced form. They differ by two electrons and a proton equivalent, and cells interconvert them during metabolism.
Yes. NAD+ is present in all living cells and is required for fundamental metabolic reactions. Its concentration varies by tissue, compartment, and time.
It indicates the oxidized form, which has a positive charge on the nicotinamide nitrogen. The reduced partner NADH lacks that charge and carries added electrons. The plus sign is part of the standard abbreviation, not a separate ion.