Thiamine is absorbed in the form of thiamine or thiamine monophosphate and transported through the plasma membrane by thiamine transporter 1 (THTR1) and thiamine transporter 2 (THTR2), which are encoded for by the genes SLC19A2 and SLC19A3, respectively. Upon cell entrance, thiamine undergoes pyrophosphorylation by thiamine pyrophosphokinase (TPK) to thiamine pyrophosphate (TPP). TPP is the active form of thiamine and serves as a cofactor of transketolase in the pentose phosphate pathway in the cytosol. TPP also functions as a cofactor for pyruvate, ketoglutarate and branched chain alpha-keto acid dehydrogenases in the mitochondrion after entrance via TPP transporter encoded by SLC25A19. This pathway was inspired by Chapter 15 (Thiamine Disorders) of the book of Blau (ISBN 3642403360 (978-3642403361)). cf3 Class of phospholipids Thiamine enters the cell via diffusion or transphosphorylation to thiamine monophosphate (TMP). d81 Phosphorylated Phosphorylation Phosphorylation 9783642403361 ISBN Physician's Guidee to the Diagnosis, Treatment, and Follow-Up of Inherited Metabolic Diseases'' ISBN 978-3-642-40337-8 , Chapter 15 2014 Blau, Nenad Duran, Marinus Gibson, K. Michael Dionisi-Vici, Carlo 10964259 PubMed Thiamine intestinal transport and related issues: recent aspects. Proc Soc Exp Biol Med 2000 Rindi G Laforenza U energy metabolic pathway PW:0000033 Pathway Ontology thiamine metabolic pathway PW:0000136 Pathway Ontology