Abstract
Introduction Thiamine (vitamin B1) is mainly known for its diphosphorylated derivatives, an essential coenzyme in energy metabolism. However, noncoenzyme roles have been suggested for this vitamin for many years. Such roles have remained hypothetical, but recent data from various sources have shed a new light on this hypothesis. First, other phosphorylated thiamine derivatives, most prominently thiamine triphosphate and adenosine thiamine triphosphate, can reach significant levels in Escherichia coli, respectively, during amino acid starvation and energy stress. Although much less is known about these compounds in animals, mammalian cells contain a highly specific soluble thiamine triphosphatase controlling cytosolic thiamine triphosphate concentrations. Second, there is now growing evidence in favour of the existence of thiamine-binding proteins with specific roles in the nervous system, possibly in the regulation of neurotransmitter release. Thiamine and some of its synthetic precursors with higher bioavailability have beneficial effects in several models of Alzheimer’s disease and may be beneficial for patients suffering from Alzheimer’s or Parkinson’s diseases. These effects might be related to non-coenzyme roles of thiamine, possibly involving thiamine-binding proteins. The aim of this review was to discuss biological
Highlights
Thiamine is mainly known for its diphosphorylated derivatives, an essential coenzyme in energy metabolism
Oxythiamine stimulates potassiumevoked acetylcholine release in the presence of Ca2+ in isolated brain slices[40]. These results suggest a coenzymeindependent effect of thiamine on neurotransmitter release, affecting at least three different neurotransmitters in different preparations ranging from fish electric organ to mammalian brain
By virtue of the role of thiamine diphosphate (ThDP) as coenzyme of several key enzymes, it is involved in most aspects of cell metabolism: energy production, ribose and nucleic acid synthesis, lipid biosynthesis and neurotransmitter synthesis to name only the most important
Summary
Thiamine (vitamin B1) is mainly known for its diphosphorylated derivatives, an essential coenzyme in energy metabolism. Thiamine and some of its synthetic precursors with higher bioavailability have beneficial effects in several models of Alzheimer’s disease and may be beneficial for patients suffering from Alzheimer’s or Parkinson’s diseases These effects might be related to non-coenzyme roles of thiamine, possibly involving thiamine-binding proteins. Like other B vitamins, thiamine (vitamin B1, Figure 1a) is an indispensable molecule for all known organisms This is mainly because, in mammalian cells, its diphosphorylated form, thiamine diphosphate (ThDP), is the coenzyme for five key metabolic enzymes (Figure 1b)[1], the most important being mitochondrial pyruvate and oxoglutarate dehydrogenase complexes as well as the cytosolic transketolase. The reason why some brain regions are more sensitive to thiamine deficiency remains unknown[3], and it was suggested that this selective vulnerability could be due to a coenzymeindependent role of thiamine or one of its derivatives[4]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call