Abstract
Regulation of hexitol catabolism was investigated in Streptococcus mutans, a cariogenic human dental plaque bacterium. Induction of hexitol catabolic enzymes and phosphoenolpyruvate:hexitol phosphotransferase and hexitol phosphate dehydrogenase activities was regulated by an inducer exclusion mechanism initiated by D-glucose and 2-deoxy-D-glucose. Kinetic analysis of the inhibitory effect of 2-deoxy-D-glucose on initial hexitol uptake illustrated that this was a noncompetitive type of inhibition. In mutant strains of S. mutans lacking phosphoenolpyruvate:glucose phosphotransferase activity, 2-deoxy-D-glucose was unable to inhibit hexitol uptake. These observations provide evidence for possible molecular mechanisms for the exclusion process.
MeSH terms
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Biological Transport / drug effects
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Deoxy Sugars / pharmacology*
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Deoxyglucose / pharmacology*
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Enzyme Induction
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Escherichia coli Proteins
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Glucose / metabolism
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Glucose / pharmacology*
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Lactates / metabolism
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Lactic Acid
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Mannitol / metabolism*
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Monosaccharide Transport Proteins
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Phosphoenolpyruvate Sugar Phosphotransferase System / biosynthesis
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Sorbitol / metabolism*
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Streptococcus mutans / metabolism*
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Sugar Alcohol Dehydrogenases / biosynthesis
Substances
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Deoxy Sugars
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Escherichia coli Proteins
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Lactates
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Monosaccharide Transport Proteins
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Lactic Acid
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Mannitol
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Sorbitol
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Deoxyglucose
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Sugar Alcohol Dehydrogenases
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sorbitol-6-phosphate dehydrogenase
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mannitol-1-phosphate dehydrogenase
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Phosphoenolpyruvate Sugar Phosphotransferase System
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mannitol PTS permease, E coli
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phosphoenolpyruvate-sorbitol phosphotransferase
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Glucose