The short version of thiol fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-18 and is reviewed periodically as new material appears.
In cells, glutathione exists mainly in a reduced form called GSH. When two GSH molecules react, they form oxidized glutathione, or GSSG, which contains a disulfide bond. The ratio of GSH to GSSG is often used as an indicator of oxidative stress. Enzymes such as glutathione peroxidase and glutathione reductase help cycle the molecule between these two states. This cycling supports antioxidant defense, detoxification of reactive molecules, and regulation of certain signaling pathways.
Glutathione is present in most tissues, with especially high concentrations in the liver. It also serves as a cofactor for some enzymes and helps transport amino acids across cell membranes. In plants and microorganisms, glutathione contributes to stress responses and metal handling. The molecule is synthesized in two ATP-dependent steps, first producing gamma-glutamylcysteine and then adding glycine. Because cysteine availability often limits synthesis, dietary and metabolic factors can influence glutathione levels. Research continues to examine how these levels relate to health and disease.
Glutathione is a small tripeptide made of glutamic acid, cysteine, and glycine. Its cysteine thiol group allows reversible oxidation and reduction, making it central to cellular redox chemistry. The reduced form, often abbreviated GSH, predominates inside most cells, while the oxidized disulfide form, GSSG, forms when two GSH molecules react. The ratio of GSH to GSSG is widely used as an indicator of oxidative stress in laboratory research, though it does not by itself diagnose a clinical condition.
Biosynthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine, forming gamma-glutamylcysteine; glutathione synthetase then adds glycine to produce the complete tripeptide. Because the peptide bond from glutamate uses the gamma-carboxyl group, glutathione resists digestion by many ordinary peptidases. Tissues vary in synthesis capacity, and the liver generally contains high concentrations relative to many other organs. This uneven distribution contributes to organ-specific differences in redox buffering and affects how experimental results are interpreted across tissue types.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione | Tripeptide of glutamate, cysteine, and glycine |
| Reduced form | GSH | Dominant intracellular thiol |
| Oxidized form | GSSG | Disulfide-linked dimer |
| Molar mass | 307.32 g/mol | For reduced glutathione |
| Functional motif | Gamma-glutamyl-cysteinyl-glycine | Gamma linkage resists many peptidases |
Vladimir Baranov is a Soviet born Canadian scientist and one of the original co-inventors of Mass cytometry technology... He co-founded DVS Sciences in 2004 (acquired by Fluidigm in 2014 and then renamed to Standard BioTools in 2022) along with Dmitry Bandura, Scott D. Tanner and Olga Ornatsky.
=== India === In the 1990s, India stopped its research in cold fusion at the Bhabha Atomic Research Centre because of the lack of consensus among mainstream scientists and the US denunciation of the research. Yet, in 2008, the National Institute of Advanced Studies recommended that the Indian government revive this research. Projects were commenced at Chennai's Indian Institute of Technology, the Bhabha Atomic Research Centre and the Indira Gandhi Centre for Atomic Research. However, there is still skepticism among scientists and, for all practical purposes, research has stalled since the 1990s. A special section in the Indian multidisciplinary journal Current Science published 33 cold fusion papers in 2015 by major cold fusion researchers including several Indian researchers. A Hyderabad-based startup, Hylenr Technologies, showcased the amplification of electrical energy into significantly more heat energy using the a LENR system. The startup is being guided by a former DRDO scientist, Padma Shri awardee, Dr. Prahlada Ramarao.
a human embryo into which a nonhuman cell or cells (or the component parts thereof) had been introduced to render the embryo's membership in the species Homo sapiens uncertain; a chimera human/animal embryo produced by fertilizing a human egg with nonhuman sperm; a chimera human/animal embryo produced by fertilizing a nonhuman egg with human sperm; an embryo produced by introducing a nonhuman nucleus into a human egg; an embryo produced by introducing a human nucleus into a nonhuman egg; an embryo containing at least haploid sets of chromosomes from both a human and a nonhuman life form; a nonhuman life form engineered such that human gametes developed within the body of a nonhuman life form; or a nonhuman life form engineered such that it contained a human brain or a brain derived wholly or predominantly from human neural tissues. The bill would have prohibited the attempts to create a human-animal chimera, the transfer or attempt to transfer a human embryo into a nonhuman womb, the transfer or attempt to transfer a nonhuman embryo into a human womb, and the transport or receipt of an animal chimera for any purpose. Proposed penalties for violations of this bill included fines and/or imprisonment of up to 10 years. The bill was referred to the Subcommittee on Crime, Terrorism, Homeland Security, and Investigations on October 11, 2016, but died there.
Sources: en.wikipedia.org
== Synthesis == While the full synthesis of opioids from naphthoquinone (Gates synthesis) or other simple organic starting materials is possible, they are tedious and uneconomical processes. Therefore, most of the opiate-type analgesics in use today are either extracted from Papaver somniferum or synthesized from those opiates, especially thebaine.
Due to its relatively short duration, testosterone propionate is now relatively little used and testosterone undecanoate is the preferred testosterone ester for intramuscular use. Testosterone undecanoate and testosterone buciclate can be injected intramuscularly as infrequently as four times per year. High doses of testosterone esters by intramuscular injection have been studied in healthy young men. Levels of testosterone with intramuscular injections of testosterone cypionate were about 700 ng/dL for 100 mg/week, 1100 ng/dL for 250 mg/week, and 2000 ng/dL for 500 mg/week. In another study, testosterone levels with 600 mg/week testosterone enanthate by intramuscular injection were 2,800–3,200 ng/dL. Intramuscular injection of testosterone propionate as an oil solution, aqueous suspension, and emulsion has been compared. Intramuscular injection of testosterone-containing biodegradable microspheres has been studied.
=== Discovery and initial characterization === Radioactivity was discovered in 1896 by Henri Becquerel in uranium, and subsequently observed by Marie and Pierre Curie in thorium and in the newly discovered elements polonium and radium. In 1899, Ernest Rutherford separated radioactive emissions into two types: alpha and beta (now beta minus), based on penetration of objects and ability to cause ionization. Alpha rays could be stopped by thin sheets of paper or aluminium, whereas beta rays could penetrate several millimetres of aluminium. In 1900, Paul Villard identified a still more penetrating type of radiation, which Rutherford termed gamma rays. In 1900, Becquerel measured the mass-to-charge ratio (m/e) for beta particles by the method of J.J. Thomson used to study cathode rays and identify the electron. He found that m/e for a beta particle is the same as for Thomson's electron, and therefore suggested that the beta particle is in fact an electron. In 1901, Rutherford and Frederick Soddy showed that alpha and beta radioactivity involves the transmutation of atoms into atoms of other chemical elements. In 1913, after the products of more radioactive decays were known, Soddy and Kazimierz Fajans independently proposed their radioactive displacement law, which states that beta (i.e., β−) emission from one element produces another element one place to the right in the periodic table, while alpha emission produces an element two places to the left.
Sources: en.wikipedia.org
This is normally a "prompt" process, but sometimes does not rapidly reach to the nuclear ground state, in which case a metastable isomer has formed. This usually occurs as a spin isomer when the formation of an intermediate excited state has a spin far different from that of the ground state. Gamma-ray emission is hindered if the spin of the post-emission state differs greatly from that of the emitting state, and if the excitation energy is low; such excited states will generally have long lives and be considered metastable. After fission, several of the fission fragments may be produced in a metastable isomeric state, after their prompt de-excitation. At the end of this process, the nuclei can populate both the ground and the isomeric states. If the half-life of an isomer is long enough, it is possible to measure its production rate, and comparing it to that of the ground state gives the so-called isomeric yield ratio.
== Adverse effects == The most common adverse effect of metformin is gastrointestinal irritation, including diarrhea, cramps, nausea, vomiting, and increased flatulence. Metformin is more commonly associated with gastrointestinal adverse effects than most other antidiabetic medications. The most serious potential adverse effect of metformin is lactic acidosis; this complication is rare, and seems to be related to impaired liver or kidney function. Metformin is not approved for use in those with severe kidney disease, but may still be used at lower doses in those with kidney problems.
Nicotine was originally isolated from the tobacco plant in 1828 by chemists Wilhelm Heinrich Posselt and Karl Ludwig Reimann from Germany, who believed it was a poison. Its chemical empirical formula was described by Melsens in 1843, its structure was discovered by Adolf Pinner and Richard Wolffenstein in 1893, and it was first synthesized by Amé Pictet and A. Rotschy in 1904. Nicotine is named after the tobacco plant Nicotiana tabacum, which in turn is named after the French ambassador in Portugal, Jean Nicot de Villemain, who sent tobacco and seeds to Paris in 1560, presented to the French King, and who promoted their medicinal use. Smoking was believed to protect against illness, particularly the plague. However, the "holy herb", tobacco, had first reached Europe by the early 1530s, brought by Spanish explorers. Following its introduction, tobacco rapidly gained popularity in Europe for its stimulating effects, fueled by nicotine's addictive and pharmacological properties and tobacco's widespread embrace as a cure-all. By the early 17th century, this allure fueled its mercilessly laborious cultivation as a cash crop in the Virginia colonies, where John Rolfe's introduction in 1612 rescued Jamestown from economic collapse and famine, transforming it into a prosperous export hub with over 20,000 pounds shipped by 1619 and laying the groundwork for transatlantic trade.
Sources: en.wikipedia.org
Glutathione is a tripeptide made from glutamate, cysteine, and glycine. Its cysteine residue provides a thiol group that is central to its redox activity. The glutamate-cysteine bond forms through the gamma-carboxyl group of glutamate.
Reduced glutathione, GSH, can donate electrons and become oxidized to GSSG. The balance between these forms reflects the cell's redox environment. A shift toward GSSG is commonly interpreted as evidence of oxidative stress, though the ratio can vary by tissue and method.
Glutathione occurs in nearly all cell types, with notable amounts in the liver. It is also present in the lungs, kidneys, and red blood cells. Concentrations differ among tissues and change with age, diet, and disease states.
GSH is the reduced form of glutathione, with a free thiol group on cysteine. GSSG is the oxidized disulfide form, created when two GSH molecules become linked. The two forms exist together, and their balance is often reported as the GSH/GSSG ratio in laboratory studies.