The Journal of General Physiology, Vol 65, 57-83, Copyright © 1975 by The Rockefeller University Press
One-way fluxes of alpha-aminoisobutyric acid in Ehrlich ascites tumor cells. Trans effects and effects of sodium and potassium
JA Jacquez
One-way fluxes in the steady state and one-way influxes at zero
intracellular concentrations were measured for alpha-aminoisobutyric acid
(AIB) in Ehrlich ascites tumor cells at 32 degrees C. The one-way fulxes
show trans effects in the concentration of AIB and are dependent on sodium
levels. The one-way fluxes for initial influx and for the steady state were
fitted with the equations derived for the frequently used two-state carrier
model. Estimates of the parameters of these equations were obtained with
use of nonlinear least squares. These gave relatively good fits of the flux
data and the data on steady-state distribution ratios. The two-state
carrier model predicted a trans inhibition of one-way influx and a trans
stimulation of one-way efflux. The former phenomenon has been demonstrated
for AIB transport in Ehrlich ascites cells and there is evidence, through
less firm, for the latter.