[Kinetic analysis of mechanisms of Na+-dependent transport of organic acids in the proximal tubules of surviving frog kidney. I. Transport of fluorescein and uranin in a sodium-free environment]

Abstract

By direct microfluorimetry, the kinetic characteristics of active transport system for organic acid were studied. A removal of sodium from the incubation medium is shown to affect the affinity between a carrier and acids (KS), and the rate of translocation of the transporting complex (which includes a carrier and a substrate) across the plasma membrane. The data obtained are in good accordance with the concept of Na+-dependent transport.