| Affiliation: | (1) Center for Cellular and Molecular Neurobiology, University of Liège, place Delcour 17, 4020 Liège, Belgium;(2) Laboratory of Enzymology, Institute of Biochemistry, National Academy of Sciences of Belarus, BLK 50, 230009 Grodno, Belarus;(3) Institute of Biology, University of Bialystok, Swierkowa 20 B, 15-950 Bialystok, Poland |
| Abstract: | In most organisms, the main form of thiamine is the coenzyme thiamine diphosphate. Thiamine triphosphate (ThTP) is also found in low amounts in most vertebrate tissues and can phosphorylate certain proteins. Here we show that ThTP exists not only in vertebrates but is present in bacteria, fungi, plants and invertebrates. Unexpectedly, we found that in Escherichia coli as well as inArabidopsis thaliana, ThTP was synthesized only under particular circumstances such as hypoxia (E. coli) or withering (A. thaliana). In mammalian tissues, ThTP concentrationsare regulated by a specific thiamine triphosphatase that we have recently characterized. This enzymewas found only in mammals. In other organisms, ThTP can be hydrolyzed by unspecific phosphohydrolases. The occurrence of ThTP from prokaryotes to mammals suggests that it may have a basic role in cell metabolism or cell signaling. A decreased content may contribute to the symptoms observed during thiamine deficiency.Received 7 March 2003; received after revision 11 April 2003; accepted 14 April 2003 |
