title: Expulsion mechanism of xylitol 5-phosphate in Streptococcus mutans.
abstract: The expulsion mechanism of xylitol 5-phosphate in Streptococcus mutans ATCC 25175 was studied using resting cells incubated in the presence of 14C-xylitol. The expulsion appeared to be a two-step process: xylitol 5-phosphate was first hydrolyzed to xylitol and inorganic phosphate, and the xylitol was subsequently expelled from the cells. The dephosphorylation step appeared to be energy-requiring and it was most likely associated with a phosphatase which was active on xylitol 5-phosphate. Two to three successive cultivations of the cells in the presence of 6% xylitol increased this enzyme activity 4.3-fold. These results are in accordance with the presence of an energy-dependent xylitol 5-phosphate cycle in S. mutans, which is regulated by exogenous xylitol.
authors.affiliation: Department of Biochemistry, University of Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Pihlanto-Leppälä
authors.forename: E
authors.initials: E
authors.lastname: Söderling
authors.forename: K K
authors.initials: KK
authors.lastname: Mäkinen
mesh_terms: D001120:Arginine / Q000494:pharmacology; D001149:Arsenates / Q000494:pharmacology; D002250:Carbon Radioisotopes; D002852:Chromatography, Ion Exchange; D004734:Energy Metabolism; D005632:Fructose / Q000494:pharmacology; D005695:Galactosephosphates / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D005958:Glucosephosphates / Q000378:metabolism; D006868:Hydrolysis; D010428:Pentosephosphates / Q000493:pharmacokinetics*; D010744:Phosphoric Monoester Hydrolases / Q000493:pharmacokinetics; D012969:Sodium Fluoride / Q000494:pharmacology; D013295:Streptococcus mutans / Q000201:enzymology / Q000378:metabolism*; D014993:Xylitol / Q000378:metabolism
chemical_list: D001149:Arsenates; D002250:Carbon Radioisotopes; D005695:Galactosephosphates; D005958:Glucosephosphates; D010428:Pentosephosphates; D005632:Fructose; C064260:xylitol 5-phosphate; C009277:sodium arsenate; D012969:Sodium Fluoride; D001120:Arginine; D010744:Phosphoric Monoester Hydrolases; D005947:Glucose; D014993:Xylitol