Effects of valinomycin on vanadate-sensitive and vanadate-resistant H+ transport in vesicles from turtle bladder epithelium: evidence for a K+/H+ exchanger.
The vanadate-sensitive component of the ATP-dependent H+ gradient formed in isolated vesicles from a urinary epithelium was abolished by valinomycin omission. This suggests that vanadate-sensitive H+ transport has an absolute requirement for intravesicular K+ and that the transport may be due to a K+/H+ exchanger. Sensitivity to the inhibitor SCH28080 supports this conclusion. On the other hand, valinomycin affects the initial velocity of vanadate-resistant transport without altering its maximum gradient. This is consistent with the development of a membrane potential consequent to electrogenic uniport H+ transport.
Youmans
S J
SJ
Department of Physiology, East Carolina University School of Medicine, Greenville, NC 27858-4354.
Barry
C R
CR
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D007700:Kinetics; D009550:Nigericin / Q000494:pharmacology; D027961:Potassium-Hydrogen Antiporters; D014426:Turtles; D001743:Urinary Bladder / Q000378:metabolism*; D014634:Valinomycin / Q000494:pharmacology*; D014638:Vanadates / Q000494:pharmacology*
D002352:Carrier Proteins; D007093:Imidazoles; D027961:Potassium-Hydrogen Antiporters; C035235:Sch 28080; D014634:Valinomycin; D014638:Vanadates; D006859:Hydrogen; D000255:Adenosine Triphosphate; D009550:Nigericin