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Thiamine

2007 Schools Wikipedia Selection. Related subjects: Food and agriculture;
General Chemistry

                       Thiamine
                       Thiamine
   Thiamine
   Systematic name   Thiamine
   Molecular formula C[12]H[17]N[4]OS
   Molecular mass    266.4 g/mol
   Density           x.xxx g/cm^3
   Melting point     248-250 °C (hydrochloride salt)
   Boiling point     xx.x °C
   CAS number        [59-43-8]
   SMILES            xxxx
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   Thiamine or thiamin, also known as vitamin B[1], is a colorless
   compound with chemical formula C[12]H[17]N[4]OS. It is soluble in water
   and insoluble in alcohol. Thiamine decomposes if heated.

   Thiamine was first discovered in 1910 by Umetaro Suzuki in Japan when
   researching how rice bran cured patients of Beriberi. He named it
   aberic acid. He did not determine its chemical composition, nor that it
   was an amine. It was first crystallized by Jansen and Donath in 1926
   (they named it aneurin, for antineuritic vitamin). Its chemical
   compostition and synthesis was finally reported by Robert R. Williams
   in 1935. He also coined the name for it, thiamin. There are three known
   thiamine phosphate derivatives: thiamine monophosphate (ThMP), thiamine
   diphosphate (ThDP) and thiamine triphosphate (ThTP).

   Thiamine diphosphate (ThDP) or thiamine pyrophosphate (TPP) is a
   coenzyme for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase,
   branched-chain alpha-keto acid dehydrogenase, and transketolase. The
   first two of these enzymes function in the metabolism of carbohydrates,
   while transketolase functions in the pentose phosphate pathway to
   synthesize NADPH and the pentose sugars deoxyribose and ribose. In
   general, TPP functions as a cofactor for enzymes that catalyze the
   dehydrogenation (decarboxylation and subsequent conjugation to Coenzyme
   A) of alpha-keto acids. TPP is synthesized by the enzyme thiamine
   pyrophosphokinase, which requires free thiamine, magnesium, and
   adenosine triphosphate.

   Thiamine triphosphate (ThTP) was long considered a specific neuroactive
   form of thiamine. However, recently it was shown that ThTP exists in
   bacteria, fungi, plants and animals suggesting a much more general
   cellular role. In particular in E. coli it seems to play a role in
   response to amino acid starvation.

Nutrition

   Also known as vitamin B1, thiamine plays an important role in helping
   the body convert carbohydrates and fat into energy. It is essential for
   normal growth and development and helps to maintain proper functioning
   of the heart and the nervous and digestive systems. Thiamine is
   water-soluble and cannot be stored in the body; however, once absorbed,
   the vitamin is concentrated in muscle tissue.

Deficiency

   Systemic thiamine deficiency can lead to myriad problems including
   neurodegeneration, wasting, and death. A lack of thiamine can be caused
   by malnutrition, alcoholism, a diet high in thiaminase-rich foods (raw
   freshwater fish, raw shellfish, ferns) and/or foods high in
   anti-thiamine factors (tea, coffee, betel nuts).

   Well-known syndromes caused by thiamine deficiency include
   Wernicke-Korsakoff syndrome and beriberi, diseases also common with
   chronic alcoholism.

Diagnostic Testing for B1 Deficiency

   A positive diagnosis test for Thiamine deficiency can be assertained by
   measuring erythrocyte levels of transketolase.

Overdose

   The only known cases of thiamine overdose occurred with thiamine
   injections. Thiamine injection may result in anaphylactic reactions.

Genetic diseases

   Genetic diseases of thiamine transport are rare but serious. Thiamine
   Responsive Megaloblastic Anaemia with diabetes mellitus and
   sensorineural deafness (TRMA) is an autosomal recessive disorder caused
   by mutations in the gene SLC19A2, a high affinity thiamine transporter.
   TRMA patients do not show signs of systemic thiamine deficiency,
   suggesting redundancy in the thiamine transport system. This has led to
   the discovery of a second high affinity thiamine transporter, SLC19A3.

   Mendelian Inheritance in Man (OMIM) 249270

Research

High doses

   The RDA in most countries is set at about 1.4 mg. However, tests on
   volunteers at daily doses of about 50 mg have shown an increase in
   mental acuity.

Benefits for autism

   Derrick Lonsdale lead a successful study on the treatment of autism
   spectrum children with thiamine. This work is controversial linking
   diet with autism.
   Retrieved from " http://en.wikipedia.org/wiki/Thiamine"
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