Thiamine

Thiamine

Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...

 triphosphate (ThTP) is found in most organisms, bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, fungi, plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s and animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s.

Function

It has been proposed that ThTP has a specific role in nerve excitability but this has never been confirmed and recent results suggest that ThTP probably plays a role in cell energy metabolism. Moreover some results suggesting that ThTP deficiency is responsible for subacute necrotizing encephalopathy or Leigh's disease

Leigh's disease

Leigh's disease, also known as Subacute Necrotizing Encephalomyelopathy , is a rare neurometabolic disorder that affects the central nervous system...

 have not been confirmed.

In E. coli, ThTP is accumulated in the presence of glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

 during amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 starvation. On the other hand, suppression of the carbon source leads to the accumulation, of adenosine thiamine triphosphate

Adenosine thiamine triphosphate

Adenosine thiamine triphosphate , or thiaminylated adenosine triphosphate, is a natural thiamine adenine nucleotide. It was discovered in Escherichia coli where it may account for up to 15 - 20 % of total thiamine under carbon starvation...

 (AThTP).

Metabolism

It has been shown that in brain ThTP is synthesized in mitochondria by a chemiosmotic mechanism, perhaps similar to ATP synthase

ATP synthase

right|thumb|300px|Molecular model of ATP synthase by X-ray diffraction methodATP synthase is an important enzyme that provides energy for the cell to use through the synthesis of adenosine triphosphate . ATP is the most commonly used "energy currency" of cells from most organisms...

.
In mammals, ThTP is hydrolyzed to ThDP by a specific thiamine triphosphatase. It can also be converted into ThDP by thiamine-diphosphate kinase

Thiamine-diphosphate kinase

In enzymology, a thiamine-diphosphate kinase is an enzyme involved in thiamine metabolism. It catalyzes the chemical reactionThus, the two substrates of this enzyme are ATP and thiamine diphosphate, whereas its two products are ADP and thiamine triphosphate....

.

History

Thiamine triphosphate (ThTP) was chemically synthesized in 1948 at a time when the only organic triphosphate known was ATP. The first claim of the existence of ThTP in living organisms was made in rat liver, followed by baker’s yeast. Its presence was later confirmed in rat tissues and in plants germs, but not in seeds, where thiamine was essentially unphosphorylated

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

. In all those studies, ThTP was separated from other thiamine derivatives using a paper chromatographic

Paper chromatography

Paper chromatography is an analytical chemistry technique for separating and identifying mixtures that are or can be colored, especially pigments. This can also be used in secondary or primary colors in ink experiments. This method has been largely replaced by thin layer chromatography, however it...

 method, followed by oxidation in fluorescent thiochrome compounds with ferricyanide

Ferricyanide

Ferricyanide is the anion [Fe6]3−.  It is also called hexacyanoferrate and in rare, but systematic nomenclature, hexacyanidoferrate...

 in alkaline solution. This method is at best semi-quantitative, and the development of liquid chromatographic methods suggested that ThTP represents far less than 10 % of total thiamine in animal tissues.