title: A constitutive thiamine metabolism mutation, thi80, causing reduced thiamine pyrophosphokinase activity in Saccharomyces cerevisiae.
abstract: We identified a strain carrying a recessive constitutive mutation (thi80-1) with an altered thiamine transport system, thiamine-repressible acid phosphatase, and several enzymes of thiamine synthesis from 2-methyl-4-amino-5-hydroxymethylpyrimidine and 4-methyl-5-beta-hydroxyethylthiazole. The mutant shows markedly reduced activity of thiamine pyrophosphokinase (EC 2.7.6.2) and high resistance to oxythiamine, a thiamine antagonist whose potency depends on thiamine pyrophosphokinase activity. The intracellular thiamine pyrophosphate content of the mutant cells grown with exogenous thiamine (2 x 10(-7) M) was found to be about half that of the wild-type strain under the same conditions. These results suggest that the utilization and synthesis of thiamine in Saccharomyces cerevisiae is controlled negatively by the intracellular thiamine pyrophosphate level.
authors.affiliation: Department of Biochemistry, Kyoto Prefectural University of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nishimura
authors.forename: Y
authors.initials: Y
authors.lastname: Kawasaki
authors.forename: K
authors.initials: K
authors.lastname: Nosaka
authors.forename: Y
authors.initials: Y
authors.lastname: Kaneko
authors.forename: A
authors.initials: A
authors.lastname: Iwashima
mesh_terms: D000135:Acid Phosphatase; D019883:Alkyl and Aryl Transferases; D002352:Carrier Proteins / Q000032:analysis; D002455:Cell Division / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D010119:Oxythiamine / Q000494:pharmacology; D010770:Phosphotransferases / Q000032:analysis; D017853:Phosphotransferases (Alcohol Group Acceptor); D017856:Phosphotransferases (Phosphate Group Acceptor); D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013836:Thiamin Pyrophosphokinase / Q000378:metabolism*; D013831:Thiamine / Q000378:metabolism* / Q000494:pharmacology; D013833:Thiamine Monophosphate / Q000032:analysis; D014166:Transferases / Q000032:analysis
chemical_list: D002352:Carrier Proteins; D003470:Culture Media; D029701:Saccharomyces cerevisiae Proteins; C026989:thiamine-binding protein; D010119:Oxythiamine; D013833:Thiamine Monophosphate; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C435495:thiamin phosphate synthase; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C059599:hydroxymethylpyrimidine kinase; D017856:Phosphotransferases (Phosphate Group Acceptor); C033532:phosphomethylpyrimidine kinase; D013836:Thiamin Pyrophosphokinase; D000135:Acid Phosphatase; C488913:PHO3 protein, S cerevisiae; C488916:PHO5 protein, S cerevisiae; D013831:Thiamine