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.
MeSH terms
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Acid Phosphatase
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Alkyl and Aryl Transferases*
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Carrier Proteins / analysis
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Cell Division / drug effects
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Chromatography, High Pressure Liquid
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Culture Media
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Dose-Response Relationship, Drug
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Oxythiamine / pharmacology
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Phosphotransferases (Alcohol Group Acceptor)*
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Phosphotransferases (Phosphate Group Acceptor)*
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Phosphotransferases / analysis
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins*
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Thiamin Pyrophosphokinase / metabolism*
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Thiamine / metabolism*
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Thiamine / pharmacology
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Thiamine Monophosphate / analysis
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Transferases / analysis
Substances
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Carrier Proteins
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Culture Media
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Saccharomyces cerevisiae Proteins
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thiamine-binding protein
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Oxythiamine
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Thiamine Monophosphate
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Transferases
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Alkyl and Aryl Transferases
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thiamin phosphate synthase
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Phosphotransferases
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Phosphotransferases (Alcohol Group Acceptor)
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hydroxymethylpyrimidine kinase
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Phosphotransferases (Phosphate Group Acceptor)
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phosphomethylpyrimidine kinase
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Thiamin Pyrophosphokinase
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Acid Phosphatase
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PHO3 protein, S cerevisiae
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PHO5 protein, S cerevisiae
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Thiamine