Vitamin B1 - Thiamine
Thiamin or Thiamine, also known as Vitamin B1 is is a water-soluble vitamin needed to process carbohydrates, fat, and protein. Every cell of the body requires vitamin B1 to form the fuel the body runs on—adenosine triphosphate (ATP). Nerve cells require vitamin B1 in order to function normally. The chemical name for this water souble vitamin is 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]- 5-(2-hydroxyethyl)-4-methylthiazolium. Thiamine consist of a pyrimidine ring and a thiazole ring connected by a one carbon link. The nitrogen in the thiazole ring has a charge of +1.
Thiamine is a coenzyme for the decarboxylation of pyruvate and the oxidation of alpha keto-glutamic acid. Lipoic acid which is formed in the liver is also required for the reactions. Patients with liver disease may show signs of B1 deficiency, possibly because of deficient synthesis of lipoic acid. In vitro, thiamine deficiency produces accumulation of pyruvate and lactate, reduction of acetate, citrate and alpha-keto-glutarate and reduced acetylcholine synthesis. Any of these metabolic changes could be involved in dysfunction.
A major biologically active form of thiamine is thiamine pyrophosphate (TPP), sometimes called thiamine diphosphate (TDP) and cocarboxylase. In thiamine pyrophosphate the hydroxyl group of thiamine is replaced by a diphosphate ester group. The reaction site of TPP is carbon 2 of the thiazole ring. The proton on this carbon is rather acidic. When this proton dissociates a carbanion is formed which readily undergoes nucleophilic addition to carbonyl groups. TPP is a coenzyme for two types of enzymes, alpha-ketoacid dehydrogenases and transketolases, both of which cleave a C-C bond adjacent to a carbonyl group releasing either carbon dioxide or an aldehyde. The resulting product is then transferred to an acceptor molecule. alpha-Ketoacid dehydrogenases decarboxylate alpha-ketoacids. The decarboxylation product is then transferred to coenzyme A (CoA). Transketolases cleaves the C-C bond adjacent to the carbonyl group of an alpha-ketosugar to give an activated glycoaldehyde. The glycoaldehyde is then combined with an aldose to give a new ketose. All known TPP dependent enzymes also require a divalent cation, commonly Mg2+.
Thiamin pyrophosphate is a coenzyme of pyruvate dehydrogenase, α-ketoglutaran dehydrogenase and transketolase. Because the first two of these enzymes are important in the metabolism of carbohydrates, thiamin deficiency causes problems with it. Thiamin deficiency also causes the diseases Wernicke-Korsakoff syndrome and beriberi, diseases common in chronic abusers of alcohol.
Thiamine aids the nervous system and is essential for the functioning of important enzymes. These enzymes have vital roles in the processes that make energy available in the body. Thiamine is essential for the transmission of certain types of nerve signal between the brain and the spinal cord. Depression, poor memory, muscle weakness and stiffness, nerve tingling, burning sensation and numbness, tiredness, headache, loss of appetite and nausea are some of the symptoms and signs of its deficiency.
Synonyms: 3-[(4-Amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethy l)-4-methylthia-zollum chloride monohydrochloride; Vitamin B1 hydrochloride
CAS No.: 67-03-8
Molecular Weight: 337.27
Chemical Formula: C12H18N4OSCl2