title: Isolation and properties of Enterococcus hirae mutants defective in the potassium/proton antiport system.
abstract: A K+/H+ antiporter regulates cytoplasmic pH in Enterococcus hirae growing at alkaline pH. Mutants defective in this antiport activity were alkaline pH sensitive. One mutant, Pop1, lacked both K+/methylamine exchange at pH 9.5 and concomitant acidification of cytoplasmic pH. Pop1 grew well at pHs below 8 but did not at pHs above 9, conditions under which cytoplasmic pH was not fully acidified.
authors.affiliation: Faculty of Pharmaceutical Sciences, Chiba University, Inage-ku, Chiba 263-8522, Japan. yoshimi@athenaeum.p.chiba-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kakinuma
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
mesh_terms: D000468:Alkalies / Q000378:metabolism; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D016983:Enterococcus / Q000235:genetics* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008744:Methylamines / Q000378:metabolism; D009154:Mutation; D011188:Potassium / Q000378:metabolism*; D027961:Potassium-Hydrogen Antiporters
chemical_list: D000468:Alkalies; D017920:Antiporters; D008744:Methylamines; D027961:Potassium-Hydrogen Antiporters; C027451:methylamine; D011188:Potassium