STUDIES ON CRYSTALLINE LENS .26. KINETIC STUDY SHOWING SATURATION OF SODIUM-PUMP

  • 1 January 1978
    • journal article
    • research article
    • Vol. 17  (2) , 186-190
Abstract
Active transport of Na+ out of rabbit lenses was shown to be carrier mediated by observing the dependence of efflux of 22Na on intracellular concentration of nonlabeled Na+ which previously was elevated by incubating lenses at 0.degree. C. Velocity of Na+ efflux increased asymptotically with increasing concentration of intracellular Na+, demonstrating carrier saturation. The maximum velocity of the Na+ pump based on Michaelis-Menten kinetics was 4.6 .mu.mol/h per lens, and the half-saturation of the carrier, which appeared to involve a single site, occurred at 36 mM.