H, K, Rb, and Li inhibit Na-dependent alanine influx across the brush border of rabbit ileum. Kinetic analysis indicates that H and K behave as competitive inhibitors of influx so that increasing the concentration of H or K in the mucosal solution is kinetically indistinguishable from decreasing the Na concentration. In addition the coupling between alanine and Na influxes is markedly reduced a...

Homoleptic coordination of the neutral diphosphines Me2P(CH2)2PMe2 and o-C6H4(PMe2)2 to the hard Li(+) and Na(+) cations is achieved using Li[Al{OC(CF3)3}4] and Na[B{3,5-(CF3)2-C6H3}4] as 'naked' cation sources. Crystallographic, solid state and solution multinuclear NMR studies confirm distorted octahedral coordination solely via three chelating diphosphines in these unique species.

In their influence on the P.D. across the protoplasm of Valonia macrophysa, Kütz., Li(+) and Cs(+) resemble Na(+), while Rb(+) and NH(4) (+) resemble K(+). The apparent mobilities of the ions in the external surface layer of Valonia protoplasm increase in the order: Cs(+), Na(+), Li(+) < Cl(-) < Rb(+) < K(+) < NH(4) (+).

The Na(+), Li(+)/H(+) antiporter of Escherichia coli (Ec-NhaA) maintains pH, Na(+) homeostasis in enterobacteria. We used isothermal titration calorimetry to perform a detailed thermodynamic analysis of Li(+) binding to Ec-NhaA and several of its mutants. We found that, in line with the canonical alternative access mechanistic model of secondary transporters, Li(+)/H(+) binding to the antiporte...

Calcineurin is a conserved, Ca2+/CaM-stimulated protein phosphatase required for Ca2+-dependent signaling in many cell types. In yeast, calcineurin is essential for growth in high concentrations of Na+, Li+, Mn2+, and OH-, and for maintaining viability during prolonged treatment with mating pheromone. In contrast, the growth of calcineurin-mutant yeast is better than that of wild-type cells in ...

The melibiose permease of Salmonella typhimurium (MelB(St)) catalyzes symport of melibiose with Na(+), Li(+), or H(+), and bioinformatics analysis indicates that a conserved Gly117 (helix IV) is part of the Na(+)-binding site. We mutated Gly117 to Ala, Pro, Trp, or Arg; the effects on melibiose transport and binding of cosubstrates depended on the physical-chemical properties of the side chain....

Internal mobility ratios of the two cations in the molten binary systems (Li, Na)Cl and (Na, K)C1 have been measured with Klemm's column method. From these and available data on the densities and conductivities the internal mobilities bLi, bNa and bK have been calculated. In (Li, Na)Cl, bLi is smaller than fcNa in the investigated composition and temperature range, and in (Na, K)C1, the Chemla ...

A method is described for the extraction of microsomal ouabain-sensitive (a- + K+)-activated ATPase from separated frog skin epithelium. The method yields a microsomal fraction containing (Na+ K+)-stimulated activity in the range of 30- 40 nmol - mg -1 - min -1 at 26 degrees C. This portion which is also ouabain sensitive, is about half of the total activity in media containing Mg2+, Na+ and K+...

We now add to the agencies by which cells take up lithium the process of cotransport with neutral amino acids via System A. In the Ehrlich cell various natural and synthetic amino acids, depending on their structure, can cause substantial accelerations of Li+ uptake over a considerable range of levels of Na+, Li+ and H+. Half the maximal augmentation of uptake, namely 1.2 mequiv. Li/kg cell wat...