Evidence for intracellular sodium pumps in permeabilized Xenopus laevis oocytes.
Ouabain binding was studied in Xenopus laevis oocytes permeabilized by detergents. The behaviour of markers showed that 10 microM-digitonin selectively disrupts the plasma membrane. In the presence of ATP, oocytes permeabilized at 10 microM-digitonin bound no more ouabain molecules than were required to abolish active 86Rb+ uptake in the intact cells. However, the ouabain binding capacity increased approx. 2-fold when inner membranes were disrupted by SDS or excess digitonin, as judged from the accompanying release of the lysosomal marker beta-hexosaminidase. The results suggest that oocytes have a large internal pool of functional sodium pumps.
Schmalzing
G
G
Max-Planck-Institut für Biophysik, Frankfurt, Federal Republic of Germany.
Kröner
S
S
Passow
H
H
D000818:Animals; D001693:Biological Transport, Active; D002463:Cell Membrane Permeability; D007425:Intracellular Membranes / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*; D014982:Xenopus laevis; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
D015222:Sodium Channels; D010042:Ouabain; D001619:beta-N-Acetylhexosaminidases