The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Sodium Pump

(or sodium-potassium pump), in biochemistry, a membrane mechanism that maintains a definite ratio of Na ⁺ and K ⁺ ions in cells by active transport of the ions against electrochemical and concentration gradients. The cells of most tissues contain more K ⁺ ions than Na ⁺ ions, whereas the fluids reaching the tissues (blood, lymph, and intercellular fluid) contain significantly higher concentrations of Na ⁺. A certain number of ions continuously enters and leaves the cells. The passive transport of cations (transfer of ions through the membrane by means of a system of special channels along the electrochemical and concentration gradients) is, on the average, compensated by active ion transport.

The function of the sodium pump is related to the transfer of metabolites into the cells and, in the case of nerve and muscle fibers, is also related to the mechanism of excitation. The active transfer of Na ⁺ from the cell is associated with the transport of K ⁺ in the opposite direction and is accomplished by a special enzyme system, the sodium-potassium transport system, which is stimulated by adenosine triphosphatase localized in the cell membrane. By hydrolyzing adenosine triphosphate (ATP), adenosine triphosphatase liberates energy, which is expended on the active transfer of cations. The working of the sodium pump on the whole depends on the level of cell metabolism.

R. N. GLEBOV

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References in periodicals archive

For example, when primary sodium pump trips, an operator expects flow of the coolant to stop.

Role of animated human machine interface in nuclear power plant simulation

The ouabain-insensitive sodium pump. Comp Biochem Physiol.

Solubilizacion y caracterizacion de la ATPasa de Na+ insensible a ouabaina a partir de membranas laterobasales de celulas de intestino delgado

Bovine adrenals contain in addition to ouabain, a second inhibitor of sodium pump. J Biol Chem 1998;273:784-92.

Digoxin-like immunoreactive factors induce apoptosis in human acute T-cell lymphoblastic leukemia

In general, animal cells routinely expend 20%-30% of their total metabolic energy on the activity of a single protein complex, the sodium pump ([Na.sup.+], [K.sup.+]-ATPase; Siems et al., 1982, 1992), and for adult marine invertebrates, the sodium pump can potentially account for 30%-70% of tissue metabolism (Baker and Connelly, 1966; Lucu and Pavicic, 1995).

Gene Expression and Enzyme Activities of the Sodium Pump During Sea Urchin Development: Implications for Indices of Physiological State

Endogenous sodium pump inhibits and blood pressure regulation: an uptake on recent progress.

De novo biosynthesis and radiolabeling of mammalian digitalis-like factors

Endogenous mammalian cardenolides are thought to be effector ligands that regulate the sodium pump as a receptor.

Strategies for developing biomarkers of heart failure

The sodium is moved into the extracellular fluid by the sodium pump and diffuses out through the junction between the two chloride cells.

Salt control: a fish story

A mechanism for direct hormonal control of the sodium pump may play an important role

Human adrenal cells in culture produce both ouabain-like and dihydroouabain-like factors

However, in recent studies using microgram amounts of purified material (5, 7), molecular mass and proton nuclear magnetic resonance ([sup.1]H NMR) [4] spectroscopic measurements have demonstrated that the adrenal and hypothalamic sodium pump inhibitors are indistinguishable from authentic ouabain.

Radioiodinated tyrosyl-ouabain and measurement of a circulating ouabain-like compound

The sodium pump [[Na.sup.+],[K.sup.+]-ATPase (NKA); [3] EC 3.6.1.37] is an integral membrane-anchored protein that couples the energy released in the enzymatic hydrolysis of ATP to the translocation of sodium and potassium ions across the cell membrane.

Sodium pump isoforms in xenotransplantation: importance of biochemical compatibility

Depending on the experimental conditions used (e.g., [K.sup.+] concentration and type of membrane isolated), the affinity constant for binding of digoxin to its receptor (the sodium pump) has been reported to be in the range [10.sup.6]-[10.sup.8] L/mol (4, 5).

Monitoring of unbound digoxin in patients treated with anti-digoxin antigen-binding fragments: a model for the future?

Sodium pump activity was estimated as ouabain-sensitive [sup.86]Rb uptake into human erythrocytes from healthy donors as previously described [12].

Isolation and characterization of a digoxin-like immunoreactive substance from human urine by affinity chromatography