Solubilization of rat kidney plasma membrane proteins associated with 3H-aldosterone.

The treatment of rat kidney plasma membranes with sodium dodecyl sulphate (SDS) did not essentially affect the ability of the membranes for 3H-aldosterone binding as compared with the intact plasma membranes (Ozegović et al., 1977). A gel filtration of 3H-aldosterone-kidney plasma membranes complex on Sepharose 6B yielded 2 protein and 2 3H-aldosterone peaks.

Postnatal development of rat kidney plasma membrane Na-K-ATPase.

The postnatal development of the sodium transport mechanism in the rat kidney, as judged by the activity of renal plasma membrane Na-K-ATPase, was studied. Highly purified kidney plasma membranes as verified by electron microscopic and enzyme examinations, were used. Na-K-ATPase activity (mumol Pi/mg protein/h) increases exponentially from 16.

In vitro inhibition of rat kidney plasma membrane Na-K-ATPase activity by triamterene.

In vitro experiments were performed to study the effect of 2,4,7-triamino-6-phenylpteridine (triamterene), a potassium sparing diuretic agent, upon the rat kidney plasma membrane Na-K-ATPase activity. Triamterene in the concentration range from 8X10(-13) mol/l to 8X10(-3) mol/l exerted a dose-dependent inhibitory effect of the rat kidney plasma membrane Na-K-Mg-ATPase and Na-K-ATPase activities--estimated IC50 values lay at about 8X10(-3) mol/l and 8X10(-7) mol/l, respectively. The diuretic did not influence the activity of Mg-ATPase, except at very high concentration.

Binding (in vitro) of some antimitotic isatin derivatives to human serum albumin.

The binding of isatin and its mustard N-Mannich base, considerably biologically active compounds, to human serum albumin has been studied by equilibrium dialysis and ultrafiltration. The influences of ligand and macromolecule concentration, temperature and pH of the incubation medium have been demonstrated. The Scatchard plot of isatin binding to albumin shows a biphasic curve which indicates the presence of at least two different binding sites on albumin molecule.