The Concentration Dependence of Active Potassium Transport in the Human Red Blood Cell

John R. Sachs; Louis G. Welt

doi:10.1172/JCI105512

Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, N. C.

†

Work done during the term of U. S. Public Health Service postdoctoral fellowship 5F2-AM-19, 537.

Present address: Dept. of Hematology, Division of Medicine. Walter Reed Army Institute of Research, Washington, D. C.

‡

Work done during tenure of U. S. Public Health Service Research Career Award 5-K6-AM-934.

Address requests for reprints to Dr. Louis G. Welt, Dept. of Medicine, University of North Carolina School of Medicine, Chapel Hill, N. C.

Submitted for publication June 6, 1966; accepted September 22, 1966.

This research was supported by U. S. Public Health Service research grants 5-RO1-HE-01301 and AM-08458 and training grant T1-AM-5054.

Find articles by Sachs, J. in: JCI | PubMed | Google Scholar

Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, N. C.

†

Work done during the term of U. S. Public Health Service postdoctoral fellowship 5F2-AM-19, 537.

Present address: Dept. of Hematology, Division of Medicine. Walter Reed Army Institute of Research, Washington, D. C.

‡

Work done during tenure of U. S. Public Health Service Research Career Award 5-K6-AM-934.

Address requests for reprints to Dr. Louis G. Welt, Dept. of Medicine, University of North Carolina School of Medicine, Chapel Hill, N. C.

Submitted for publication June 6, 1966; accepted September 22, 1966.

This research was supported by U. S. Public Health Service research grants 5-RO1-HE-01301 and AM-08458 and training grant T1-AM-5054.

Find articles by Welt, L. in: JCI | PubMed | Google Scholar

The relation between the active potassium influx in the human red blood cell and the extracellular potassium concentration does not appear to be consistent with the Michaelis-Menten model, but is adequately described by a model in which two potassium ions are required simultaneously at some site or sites in the transport mechanism before transport occurs. The same type of relation appears to exist between that portion of the sodium outflux that requires the presence of extracellular potassium and the extracellular potassium concentration. Rubidium, cesium, and lithium, which are apparently transported by the same system that transports potassium, stimulate the potassium influx when both potassium and the second ion are present at low concentrations, as is predicted by the two-site model.