Sodium pumping

H. P. Maffei, C. W. Punk, and J. L. BaUif, Sodium Eemoval Disassembly and Examination Of the Ferrmi Secondary Sodium Pump, Report 1974, HEDL-TC-133, available from National Technical Information Service, Washington, D.C. 

Other stmctural variations in both series are the stereochemistry at C3 and the degree of oxidation on the nucleus and side chains. Cardiac steroids probably exert their inotropic effects by acting as specific, noncompetitive inhibitors of — ATPases, known as sodium pumps, and thus... 

The Na - and K -dependent ATPase comprises two subunits, an a-subunit of 1016 residues (120 kD) and a 35-kD /3-subunit. The sodium pump actively... 

ATP hydrolysis occurs on the cytoplasmic side of the membrane (Figure 10.8), and the net movement of one positive charge outward per cycle makes the sodium pump electrogenic in nature. 

ATPase inhibitor. In such patients, inhibition of the sodium pump in the cells lining the blood vessel wall results in accumulation of sodium and calcium in these cells and the narrowing of the vessels to create hypertension. An 8-year study aimed at the isolation and identification of the agent responsible for these effects by researchers at the University of Maryland Medical School and the Upjohn Laboratories in Michigan recently yielded a surprising result. Mass spectrometric analysis of compounds isolated from many hundreds of gallons of blood plasma has revealed that the hypertensive agent is ouabain itself or a closely related molecule ... 

Cardiac glycosides (CG) are potent and highly specific inhibitors of the intrinsic plasma membrane Na+/K+-ATPase, also known as the sodium pump. They modulate electrophysiological properties of the heart and its contractile functions. 

The reactivity of the sodium pump isoforms toward ouabain can significantly differ between certain isoenzymes. The al-isoform from rat is reported to be 100-fold more resistant to ouabain than a2- or a3-isoform. In other species like rabbit, pig, dog or human these differences are not as distinct as in rat, due to a more sensitive al-isoform. At least two different types of ouabain binding sites are reported for the Na+/fC+-ATPase [1]. 

Interactions with the cytoskeleton seem to be responsible for the processing and the targeting of the Na+/fC+-ATPase to the appropriate compartment structures. Protein kinases are considered to play an essential role in modulation of the sodium pump. 

Na+/K+-ATPase sodium pump Sodium- and potassium-activated adenosine 5 -triphosphatase EC 3.6.1.37. 

Scheiner-Bobis G (2002) The sodium pump. Its molecular properties and mechanics of ion transport. Eur J Biochem. 269 2424—2433... 

Mijatovic T, Roland I, Van Quaquebeke E et al (2007) The alphal subunit of the sodium pump could represent a novel target to combat non-small cell lung cancers. J Pathol 212 170-9... 

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Vanadate, dioxybis(oxamato)-bond-length ratios, 1,57 Vanadate, heptacyano-potassium salt structure, I, 72 Vanadate, hexafluoro-dipotassium salt history, I, 21 potassium salt history, 1,21 tripotassium salt history, 1,21 Vanadate, pentachloro-stereochemistry, 1,40 Vanadate, pentafluorooxy-stereochemistry, I, 50 Vanadates biochemistry, 3,456 calcium/magnesium ATPase inhibition, 6, 567 competition with phosphates physiology, 6,665 protonation, 3,1026 sodium pump, 6, 557 in uranium purification from ore, 6, 899 Vanadates, hexafluoro-, 3. 482,531 Vanadates, oxoperoxo-, 3,501 Vanadates, pentacarbonyl-, 3, 457 Vanadium biology, 6,665 determination, 1. 548 extraction... 

Muscle activity is accompanied by cellular pumping of sodium ions. The energy requirements of the sodium pump have been studied on an individual cardiac muscle mounted inside a tiny differential calorimeter and stimulated by electrical impulses. The heat evolved was different in the presence and absence of a known inhibitor of the sodium pump. 

Kaplan, J.H. and DeWeer, P. (Eds.) (1991) The Sodium Pump Structure, Mechanism, and Regulation, Rockefeller University Press, New York. 

Clarke RJ, Kane DJ (2007) Two gears of pumping by the sodium pump. Biophys J 93 41874-196... 

There are also Na+ pump y-subunits, a family of=15 kDa proteolipids that can associate with sodium pump a-subunits. However they are not necessary for pump activity nor are they expressed in all cells. The y-subunits are classed as members of the FXYD gene family and several are expressed in brain [5]. The kidney expresses almost exclusively Na+,K+ pumps with arsubunits throughout the functionally diverse segments of the nephron, but different y-subunits are expressed in different segments. From this it is inferred that different y-subunits optimize the sodium pump for operation under the varying ionic environments [6]. 

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