[Character of K+ absorption and its interaction with membrane protein pumps in Escherichia coli, grown under anaerobic conditions in the presence of nitrate].
The character of H(+)-K(+)-exchange in E.coli, grown in anaerobic conditions in the presence of sodium nitrate and performed a nitrate respiration, has been studied. The K+ uptake has been shown to occur by one step, to be not inhibited by N,N'-dicyclohexylcarbodiimide, but to be stopped by arsenate and protonophore. It has K(m) of 4.5 mM, K+ accumulation in cell is more than 200 mM and K+ distribution between the cytoplasm and the medium is more than 10(3) (K+ equilibrium potential is achieved 190 mV). To switch on a mechanism of K+ uptake is depended on osmotic shock and carried out upon positive as well as negative shocks in spheroplasts. A H+ efflux occurs with constant rate while glucose is in the medium and a stoichiometry for the initial H+ to K+ fluxes is variable upon a different experimental conditions. In spite of H(+)-K(+)-exchange in anaerobically grown E.coli, a production of H2 in bacteria is not observed, an ATPase activity of isolated membranes sensitive, to N,N'-dicyclohexylcarbodiimide is not stimulated by K+ and lost in E.coli mutant with an unc-deletion. It is concluded that H+ and K+ transfer through the membranes in E.coli performed a nitrate respiration, occur through different systems-a respiration chain and the TrkA system of K+ uptake. The latest operates itself, has no ATPase activity and interacts with membrane proton pumps indirectly using transmembrane proton gradient (delta mu H+) as a driving force as well as ATP as a regulator of activity. A sensitivity of this system to osmotic shock is lost under destruction of periplasmic space.
Bagramian
K A
KA
Vasilian
A V
AV
Trchunian
A A
AA
D017920:Antiporters / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D027961:Potassium-Hydrogen Antiporters; D054328:Proton Pump Inhibitors; D017494:Proton Pumps / Q000378:metabolism*; D020917:Receptor, trkA
D017920:Antiporters; D002352:Carrier Proteins; D008565:Membrane Proteins; D009566:Nitrates; D027961:Potassium-Hydrogen Antiporters; D054328:Proton Pump Inhibitors; D017494:Proton Pumps; D004024:Dicyclohexylcarbodiimide; D020917:Receptor, trkA; D011188:Potassium
Kharakter pogloshcheniia K+ i ego vzaimodeĭstvie s protonnymi nasosami membrany u bateri i Escherichia coli, vyrashchennykh v anaérobnykh usloviiakh v prisutstvii nitrata.