Everything below concerns NAD+/NADH ratio. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
In glycolysis, the tricarboxylic acid cycle, and fatty acid oxidation, NAD+ is reduced to NADH at specific dehydrogenase steps. NADH then delivers electrons to the mitochondrial electron transport chain, mainly at complex I, supporting oxidative phosphorylation and ATP production. The balance between NAD+ and NADH, often expressed as a ratio, influences metabolic flux and redox homeostasis in different cellular compartments. Cytosolic and mitochondrial pools are connected but not identical, and their ratios can differ substantially because of compartment-specific enzymes and transport systems.
Beyond redox chemistry, NAD+ serves as a substrate for enzymes that cleave the molecule and transfer its ADP-ribose moiety or remove acetyl groups. Sirtuins consume NAD+ during deacetylation, poly(ADP-ribose) polymerases use it in DNA damage responses, and CD38 enzymes hydrolyze it to signaling metabolites. These consumption pathways mean that NAD+ availability can influence gene regulation, DNA repair, and calcium signaling. Cellular NAD+ concentrations decline in some tissues with age in animal models, but whether this decline is a cause or consequence of aging in humans remains an active open question.
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.
NAD+ is commonly measured by high-performance liquid chromatography with ultraviolet detection, often at 254 or 260 nm. Enzymatic cycling assays provide higher sensitivity by coupling NAD+ to a reporter reaction. Mass spectrometry can distinguish NAD+ from close analogues and confirm isotope labeling. Sample preparation usually involves rapid quenching of metabolism to prevent interconversion with NADH. Because NAD+ and NADH differ by one hydride, extraction conditions strongly affect the measured ratio.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | β-NAD+, coenzyme I, DPN | DPN stands for diphosphopyridine nucleotide; older literature uses this term. |
| CAS Registry Number | 53-84-9 | Free acid form of β-nicotinamide adenine dinucleotide. |
| Molecular formula | C21H27N7O14P2 | Anhydrous free acid; molar mass 663.43 g/mol. |
| Appearance | White to off-white powder | Crystalline solid; may absorb moisture from air. |
| Solubility | Freely soluble in water | Insoluble in most nonpolar organic solvents. |
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.
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.
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.
The molecule was first described in the early twentieth century as a factor that promoted fermentation in yeast extracts. Later work linked it to hydrogen transfer and to the oxidation of nutrients in living tissues. Its structure was resolved as a dinucleotide, which explained why it could accept and donate electrons at specific enzyme sites. Today, NAD+ is recognized as a central substrate and signaling precursor, not merely a metabolic cofactor. Whether all observed NAD+ changes reflect causal signaling remains an open question.
Related compounds include NADH, the reduced form, and NADP+, which carries an additional phosphate group. NADP+ and NADPH often serve in biosynthetic and antioxidant reactions, while NAD+ and NADH are more associated with energy-yielding catabolism. Nicotinamide, nicotinic acid, and nicotinamide riboside are precursors that can enter salvage pathways. The exact contribution of dietary precursors to tissue NAD+ pools is an area of active investigation. Some studies measure labeled precursors to trace those routes.
Both meats and vegetables went through a similar freezing process. They would start by laying all the different foods on rocks and during the cold nights in high altitudes with dry air they would freeze. The next morning, a combination of the thin dry air and the heat from the sun would melt the ice and evaporate all the moisture.They would also trample over it in the morning to get any extra moisture out. The process of freeze-drying was important for transportation and storage. The high elevation (low atmospheric pressure) and low temperatures of the Andes mountains is what allowed them to take advantage of this process.
=== Bioplastics === Various polymers can be created from algae, which can be especially useful in the creation of bioplastics. These include hybrid plastics, cellulose-based plastics, poly-lactic acid, and bio-polyethylene. Several companies have begun to produce algae polymers commercially, including for use in flip-flops and in surf boards. Even algae is also used to prepare various polymeric resins suitable for coating applications.
There is no scientific evidence that HCG is effective in the treatment of obesity. The meta-analysis found insufficient evidence supporting the claims that HCG is effective in altering fat-distribution, hunger reduction, or in inducing a feeling of well-being. The authors stated "…the use of HCG should be regarded as an inappropriate therapy for weight reduction…" In the authors opinion, "Pharmacists and physicians should be alert on the use of HCG for Simeons therapy. The results of this meta-analysis support a firm standpoint against this improper indication. Restraints on physicians practicing this therapy can be based on our findings." According to the American Society of Bariatric Physicians, no new clinical trials have been published since the definitive 1995 meta-analysis. The scientific consensus is that any weight loss reported by individuals on an "HCG diet" may be attributed entirely to the fact that such diets prescribe calorie intake of between 500 and 1,000 calories per day, substantially below recommended levels for an adult, to the point that this may risk health effects associated with malnutrition.
Several methods for predicting drug metabolism have also been proposed in the scientific literature. Due to the large number of drug properties that must be simultaneously optimized during the design process, multi-objective optimization techniques are sometimes employed. Finally because of the limitations in the current methods for prediction of activity, drug design is still very much reliant on serendipity and bounded rationality.
In 2018, researchers at Georgia Institute of Technology identified three molecular candidates for the bases that might have formed an earliest version of proto-RNA: barbituric acid, melamine, and 2,4,6-triaminopyrimidine (TAP). These three molecules are simpler versions of the four bases in current RNA, which could have been present in larger amounts and could still be forward-compatible with them but may have been discarded by evolution in exchange for more optimal base pairs. Specifically, TAP can form nucleotides with a large range of sugars. Both TAP and melamine base pair with barbituric acid. All three spontaneously form nucleotides with ribose. A 2024 study synthesized a 45-nucleotide polymerase ribozyme named QT45, discovered from random sequence pools, that catalyzes general RNA-templated RNA synthesis. It can synthesize both its complementary strand and a copy of itself with fair accuracy. The authors speculate that polymerase ribozymes are more abundant in RNA sequence space than previously thought.
Sources: en.wikipedia.org
== Notable people == Michael Dunn, Oscar- and Tony-nominated American actor, The Wild Wild West, Star Trek Warwick Davis, English actor and TV presenter, Willow, Return of the Jedi, Leprechaun film series. His two children also have SED. Lenny Rush, English actor, Am I Being Unreasonable? Natalia Grace, Ukrainian-born American with dwarfism, The Curious Case of Natalia Grace Alexander Katan, Dutch Jewish accountant, teacher, and translator who was murdered by the Nazis during the Holocaust, photos of him were notoriously on display in various museums.
Anemia (hematocrit <0.28) Thrombocytopenia (platelet count < 100 x 109/L) A significant platelet function defect other than aspirin Once anemia and thrombocytopenia have been excluded, further evaluation to exclude von Willebrand disease and inherited/acquired platelet dysfunction can be made.
From 1995 to 1996, he was the voice of the character Halcyon Renard in the Disney adventure cartoon Gargoyles. Culp also appeared on Walker, Texas Ranger as Lyle Pike in the episode "Trust No One" (1995). From 1996 to 2004, Culp had a recurring role on Everybody Loves Raymond as Warren Whelan, the father of Debra Barone and father-in-law of Ray Barone. He played a CIA agent and the father of Dr. Jesse Travis on Diagnosis: Murder in the episode "Discards" (1997), along with Barbara Bain, Robert Vaughn, and Patrick Macnee. In 2007, he did a voice-over on the stop-motion sketch comedy Robot Chicken.
Things like ideologies, law, government, money and the economy are built on language; they exist because there are stories that billions of people believe. The current prevalence of misinformation suggests that an AI could use language to convince people to believe anything, even to take actions that are destructive. Geoffrey Hinton said in 2025 that modern AI is particularly "good at persuasion" and getting better all the time. He asks, "Suppose you wanted to invade the capital of the US. Do you have to go there and do it yourself? No. You just have to be good at persuasion." The opinions amongst experts and industry insiders are mixed, with sizeable fractions both concerned and unconcerned by risk from eventual superintelligent AI. Personalities such as Stephen Hawking, Bill Gates, and Elon Musk, as well as AI pioneers such as Geoffrey Hinton, Yoshua Bengio, Stuart Russell, Demis Hassabis, and Sam Altman, have expressed concerns about existential risk from AI. In May 2023, Geoffrey Hinton announced his resignation from Google in order to be able to "freely speak out about the risks of AI" without "considering how this impacts Google". He notably mentioned risks of an AI takeover, and stressed that in order to avoid the worst outcomes, establishing safety guidelines will require cooperation among those competing in use of AI. In 2023, many leading AI experts endorsed the joint statement that "Mitigating the risk of extinction from AI should be a global priority alongside other societal-scale risks such as pandemics and nuclear war".
Sources: en.wikipedia.org
Chronic poisoning is long-term repeated or continuous exposure to a poison where symptoms do not occur immediately or after each exposure. The person gradually becomes ill, or becomes ill after a long latent period. Chronic poisoning most commonly occurs following exposure to poisons that bioaccumulate, or are biomagnified, such as mercury, gadolinium, and lead.
== External links == "Formylpeptide Receptors: FPRL1". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
== Classification == Skeletons can be defined by several attributes. Solid skeletons consist of hard substances, such as bone, cartilage, or cuticle. These can be further divided by location; internal skeletons are endoskeletons, and external skeletons are exoskeletons. Skeletons may also be defined by rigidity, where pliant skeletons are more elastic than rigid skeletons. Fluid or hydrostatic skeletons do not have hard structures like solid skeletons, instead functioning via pressurized fluids. Hydrostatic skeletons are always internal.
In the United States, subsidization of corn, soy, wheat, and rice through the U.S. farm bill has made the main sources of processed food cheap compared to fruits and vegetables. Calorie count laws and nutrition facts labels attempt to steer people toward making healthier food choices, including awareness of how much food energy is being consumed. Obese people consistently under-report their food consumption as compared to people of normal weight. This is supported both by tests of people carried out in a calorimeter room and by direct observation.
=== Gastrointestinal === Isotretinoin may cause non-specific gastrointestinal symptoms including nausea, diarrhea, and abdominal pain. The drug is associated with inflammatory bowel disease (IBD)—ulcerative colitis, but not Crohn's disease. There are also reports of people developing irritable bowel syndrome (IBS) and worsening of existing IBS.
Sources: en.wikipedia.org
NAD+ is an oxidized dinucleotide coenzyme that carries electrons in metabolic reactions. It is also consumed by signaling enzymes, including sirtuins and PARPs. Its reduced form is NADH.
NAD+ is the oxidized form and can accept a hydride equivalent. NADH is the reduced form and donates electrons to the electron transport chain. The two forms cycle between each other during cellular respiration.
In mammals, NAD+ is synthesized mainly through salvage pathways using nicotinamide, nicotinamide riboside, or nicotinic acid. Tryptophan can also contribute through a de novo route. The salvage pathway is often considered the primary source in many tissues.
NAD+ and NADH can interconvert quickly after a sample is collected, which can alter the measured ratio. Rapid quenching and cold handling limit enzymatic and chemical changes.