Chemically, thiamine (C₁₂H₁₇N₄OS) consists of two heterocyclic rings: a substituted pyrimidine and a thiazole, connected by a methylene bridge. It is a water-soluble vitamin and is unstable in alkaline conditions and sensitive to heat and oxidative agents.
In the body, thiamine is rapidly phosphorylated to its biologically active form, thiamine pyrophosphate (TPP)—also called thiamine diphosphate (TDP). Other important derivatives include:
Thiamine monophosphate (TMP) – An intermediate in thiamine metabolism.
Thiamine triphosphate (TTP) – Found in nervous tissue; may play roles in membrane function and signal transmission.
Adenosine thiamine triphosphate (AThTP) – Observed in stress responses in bacteria and mammals.