Nutritional disorder, with nerve and heart impairment, caused by thiamin deficiency. Its name is from the Sinhalese word for “extreme weakness.” Symptoms include fatigue, digestive problems, and limb numbness and weakness. Dry beriberi involves gradual long-nerve degeneration, with muscle atrophy and loss of reflexes. Wet beriberi is more acute, with edema from cardiac failure and poor circulation. Thiamin occurs widely in food but is lost in processing; a well-balanced diet high in unprocessed foods can prevent beriberi. In Western countries, chronic alcoholism is the most common cause.
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Organic compound, part of the vitamin B complex, necessary in carbohydrate metabolism. It carries out these functions in its active form, as a component of the coenzyme thiamin pyrophosphate. Its molecular structure includes a substituted pyridine ring and a thiazole ring. Thiamin is found most abundantly in whole cereal grains and certain other seeds. Deficiency leads to beriberi.
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- thiamine triphosphate + H2O thiamine diphosphate + phosphate
Thus, the two substrates of this enzyme are thiamine triphosphate and H2O, whereas its two products are thiamine diphosphate and phosphate.
This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is thiamine-triphosphate phosphohydrolase. This enzyme participates in thiamine metabolism.
Structural studies
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .
References
- Hashitani Y, Cooper JR "The partial purification of thiamine triphosphatase from rat brain". J. Biol. Chem. 247 2117–9.
External links
- The CAS registry number for this enzyme class is .
Gene Ontology (GO) codes
This article is licensed under the GNU Free Documentation License.
Last updated on Sunday December 09, 2007 at 14:36:04 PST (GMT -0800)
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