Treatment of isolated canine renal Na,K-ATPase with a stable diazomethane analog, 4-(diazomethyl)-7-(diethylamino)-coumarin (DEAC), results in enzyme inactivation. The inactivation rate was dramatically increased when the enzyme was treated with DEAC in the presence of ATP and Mg2+ (in imidazole buffer) or Pi and Mg2+, conditions which produce enzyme phosphorylation. Inactivation in the presenc...

Unprecedented homoleptic octathioether macrocyclic coordination to Na(+) in [Na([24]aneS8)](+) has been achieved by using Na[B{3,5-(CF3)2-C6H3}4] as a source of "naked" Na(+) ions and confirmed crystallographically, with d(Na-S) = 2.9561(15)-3.0524(15) Å. Density functional theory calculations show that there is electron transfer from the S 3p and C 2p valence orbitals of the ligand to the 3s a...

The demineralization kinetics of deproteinized lobster shells using CO2 were studied. Demineralization reaction proceeds until the concentration of Ca+2 in solution reaches an equilibrium value. The introduction of a cation exchange resin (cationite), in an open system for CO2, allows replacement of the solution Ca 2+ ions by Na+ ions, whereby the equilibrium shifts and an effective dissolution...

dft calculations were used to investigate adsorptionof  f-, cl-, li+ and na+ ions on the exterior surface of mg12o12 nanocage in the gas phase and water media. the most favorite position for adsorption of the studied anions and cations are atop of mg and o atoms of mg12o12, respectively. the strongest interaction is obtained when fluoride is located atop of mg atom with the adsorption energy of...

Phosphorylation of red cell membranes at ambient temperatures with micromolar [32P]ATP in the presence of Na ions produced phosphoenzyme that was dephosphorylated rapidly upon the addition of ADP or K ions. However, as first observed by Blostein (1968, J. Biol. Chem., 243:1957), the phosphoenzyme formed at 0 degrees C under otherwise identical conditions was insensitive to the addition of K ion...

Na(+)/K(+) pump or sodium- and potassium-activated adenosine 5'-triphosphatase (Na(+), K(+)-ATPase), its enzymatic version, is a crucial protein responsible for the electrochemical gradient across the cell membranes. It is an ion transporter, which in addition to exchange cations, is the ligand for cardenolides. This enzyme regulates the entry of K(+) with the exit of Na(+) from cells, being th...

The Na+ and Cl- dependence of imipramine binding and dissociation were determined in platelet plasma membrane vesicles. Equilibrium imipramine binding affinity depends on Na+ binding to two non-interacting, low-affinity sites. Binding of a single Cl- ion also enhances imipramine affinity. Imipramine dissociation is inhibited by Na+ and Cl-, indicating that both ions can bind after imipramine. O...

Potassium channels play crucial roles in physiology, and one of their more important roles is to repolarize the membrane after an action potential in excitable cells (Hille, 2001). During an action potential, Na + chan­ nels open first and depolarize the cell membrane, which is followed closely by their inactivation and sub­ sequent opening of K + channels that repolarize the cell membrane by a...

The Na/K-ATPase or Na, K-pump utilizes the free energy of hydrolysis of ATP to actively transport Na and K ions across mammalian cell membranes. This function underlies essentially all of mammalian cell physiology. For example, in the kidney the Na, K-pump controls body Na and K balance, extracellular volume and blood pressure. The Na/K-ATPase is the receptor of digitalis steroids used to treat...

With a mean precipitation rate, much lower than that of the world, Iran is among the countries that face severe water challenges. The present study has dealt with the evaluation of hydrochemistry of Faryab spring water in Hormozgan Province, Iran. Four different composite water samples have been analyzed to detect major anions, cations, total dissolved solids, electrical conductivity, pH, and s...