title: Photoinactivation of the thiamine transport system in Saccharomyces cerevisiae with 4-azido-2-nitrobenzoylthiamine.
abstract: A newly synthesized photoreactive thiamine derivative, 4-azido-2-nitrobenzoylthiamine was found to be a competitive inhibitor of the thiamine transport system in Saccharomyces cerevisiae, exhibiting an apparent Ki of 36 nM. When exposed to visible light, 4-azido-2-nitrobenzoylthiamine irreversibly inactivated the thiamine transport. 4-Azido-2-nitrobenzoylthiamine-dependent photoinactivation of thiamine transport was partially protected by thiamine, but not by the nitrene-trapping reagent p-aminobenzoate. On the other hand, the irradiation of the yeast cells in the presence of 4-azido-2-nitrobenzoylthiamine did not significantly lead to inactivation of the biotin transport system. The results suggest that 4-azido-2-nitrobenzoylthiamine is a specific irreversible inhibitor of the thiamine transport system in Saccharomyces cerevisiae.
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D008027:Light; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000528:radiation effects*; D013831:Thiamine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology
chemical_list: C031810:4-azido-2-nitrobenzoylthiamine; D013831:Thiamine