thiamine thiamine thiamine, also known as thiamin and vitamin b1, is a vitamin, an essential micronutrient for humans and animals. it is found in food and commercially synthesized to be a dietary supplement or medication. phosphorylated forms of thiamine are required for some metabolic reactions, including the breakdown of glucose and amino acids. thiamineskeletal formula and ball-and-stick model of the thiamine cationclinical datapronunciation/ˈθaɪ.əmɪn/ thy-ə-min other namesvitamin b1, aneurine, thiaminahfs/drugs.commonographlicense data us dailymed: thiamine us fda: thiamine routes ofadministrationby mouth, iv, imdrug classvitaminatc codecation: a11da01 (who) legal statuslegal status us: otc pharmacokinetic databioavailability3.7% to 5.3% (thiamine hydrochloride)identifiers iupac name 2--4-methyl-1,3-thiazol-3-ium-5-yl]ethanol cas numbercation: 70-16-6 y 67-03-8 (cl−.hcl)cl− salt: 59-43-8 ypubchem cidcation: 1130cl− salt: 6042drugbankcation: db00152chemspidercation: 1098uniication: 4abt0j945jcl− salt: x66nso3n35 ykeggcation: c00378chebication: chebi:18385chemblcation: chembl1547comptox dashboard (epa)cation: dtxsid50220251 chemical and physical dataformulac12h17n4os+molar mass265.36 g·mol−13d model (jsmol)cation: interactive image smiles cation: cc2ncc(c1csc(cco)c1c)c(n)n2 inchi cation: inchi=1s/c12h17n4os/c1-8-11(3-4-17)18-7-16(8)6-10-5-14-9(2)15-12(10)13/h5,7,17h,3-4,6h2,1-2h3,(h2,13,14,15)/q+1 ykey:jzrwcgzrtzmzeh-uhfffaoysa-n food sources of thiamine include whole grains, legumes, and some meats and fish. grain processing removes much of the vitamin content, so in many countries cereals and flours are enriched with thiamine. supplements and medications are available to treat and prevent thiamine deficiency and disorders that result from it include beriberi and wernicke encephalopathy. they are also used to treat maple syrup urine disease and leigh syndrome. supplements and medications are typically taken by mouth, but may also be given by intravenous or intramuscular injection. thiamine supplements are generally well tolerated. allergic reactions, including anaphylaxis, may occur when repeated doses are given by injection. thiamine is on the world health organization's list of essential medicines. it is available as a generic medication, and in some countries as a non-prescription dietary supplement. definition thiamine is one of the b vitamins and is also known as vitamin b1. it is a cation that is usually supplied as a chloride salt. it is soluble in water, methanol and glycerol, but practically insoluble in less polar organic solvents. in the body, thiamine can form derivatives; the most well-characterized of which is thiamine pyrophosphate (tpp), a coenzyme in the catabolism of sugars and amino acids. the chemical structure consists of an aminopyrimidine and a thiazolium ring linked by a methylene bridge. the thiazole is substituted with methyl and hydroxyethyl side chains. thiamine is stable at acidic ph, but it is unstable in alkaline solutions and from exposure to heat. it reacts strongly in maillard-type reactions. oxidation yields the fluorescent derivative thiochrome, which can be used to determine the amount of the vitamin present in biological samples. deficiency main article: thiamine deficiency well-known disorders caused by thiamine deficiency include beriberi, wernicke–korsakoff syndrome, optic neuropathy, leigh's disease, african seasonal ataxia (or nigerian seasonal ataxia), and central pontine myelinolysis. symptoms include malaise, weight loss, irritability and confusion. in western countries, chronic alcoholism is a risk factor for deficiency. also at risk are older adults, persons with hiv/aids or diabetes, and those who have had bariatric surgery. varying degrees of thiamine insufficiency have been associated with the long-term use of diuretics. biological functions thiamine monophosphate (thmp) five natural thiamine phosphate derivatives are known: thiamine monophosphate (thmp), thiamine pyrophosphate (tpp), thiamine triphosphate (thtp), adenosine thiamine diphosphate (athdp) and adenosine thiamine triphosphate (athtp). they are involved in many cellular processes. the best-characterized form is tpp, a coenzyme in the catabolism of sugars and amino acids. while its role is well-known, the non-coenzyme action of thiamine and derivatives may be realized through binding to proteins which do not use that mechanism. no physiological role is known for the monophosphate except as an intermediate in cellular conversion of thiamine to the di- and triphosphates. thiamine pyrophosphate thiamine pyrophosphate (tpp)the ylide form of tpp thiamine pyrophosphate (tpp), also called thiamine diphosphate (thdp), participates as a coenzyme in metabolic reactions, including those in which polarity inversion takes place. its synthesis is catalyzed by the enzyme thiamine diphosphokinase according to the reaction thiamine + atp → tpp + amp (ec 2.7.6.2). tpp is a coenzyme for several enzymes that catalyze the transfer of two-carbon units and in particular the dehydrogenation (decarboxylation and subsequent conjugation with coenzyme a) of 2-oxoacids (alpha-keto acids). the mechanism of action of tpp as a coenzyme relies on its ability to form an ylide. examples include: present in most species pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase (also called α-ketoglutarate dehydrogenase) branched-chain α-keto acid dehydrogenase 2-hydroxyphytanoyl-coa lyase transketolase present in some species: pyruvate decarboxylase (in yeast) several additional bacterial enzymes the enzymes transketolase, pyruvate dehydrogenase (pdh), and 2-oxoglutarate dehydrogenase (ogdh) are important in carbohydrate metabolism. the cytosolic enzyme transketolase is central to the pentose phosphate pathway, a major route for the biosynthesis of the pentose sugars deoxyribose and ribose. the mitochondrial pdh and ogdh are part of biochemical pathways that result in the generation of adenosine triphosphate (atp), which is the main energy transfer molecule for the cell. pdh links glycolysis to the citric acid cycle, while the reaction catalyzed by ogdh is a rate-limiting step in the citric acid cycle. in the nervous system, pdh is also involved in the synthesis of myelin and the neurotransmitter acetylcholine. thiamine triphosphate thiamine triphosphate (thtp) thtp is implicated in chloride channel activation in the neurons of mammals and other animals, although its role is not well understood. thtp has been found in bacteria, fungi and plants, suggesting that it has other cellular roles. in escherichia coli, it is implicated in the response to amino acid starvation. adenosine derivatives adenosine thiamine diphosphate (athdp)adenosine thiamine triphosphate (athtp) athdp exists in small amounts in vertebrate liver, but its role remains unknown. athtp is present in e. coli, where it accumulates as a result of carbon starvation. in this bacterium, athtp may account for up to 20% of total thiamine. it also exists in lesser amounts in yeast, roots of higher plants and animal tissue. medical uses