Olga D. Lopina

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A partially purified Na,K-ATPase preparation from rat heart containing α1- and α2-isoforms of the enzyme was shown to include both subunits in S-glutathionylated state. Glutathionylation of the α1-subunit (but not of the α2-subunit) was partially removed when the preparation was isolated in the presence of dithiothreitol. The addition of oxidized(More)
Active transport of sodium and potassium ions by Na,K-ATPase is accompanied by the enzyme conformational transition between E1 and E2 states. ATP and ADP bind to Na,K-ATPase in the E1 conformation with similar affinity but the properties of enzyme in complexes with these nucleotides are different. We have studied thermodynamics of Na,K-ATPase binding with(More)
Side-by-side with inhibition of the Na+,K+-ATPase ouabain and other cardiotonic steroids (CTS) can affect cell functions by mechanisms other than regulation of the intracellular Na+ and K+ ratio ([Na+]i/[K+]i). Thus, we compared the doseand time-dependences of the effect of ouabain on intracellular [Na+]i/[K+]i ratio, Na+,K+-ATPase activity, and(More)
It was shown earlier that a 67-kDa protein purified from mouse kidney using polyclonal antibodies against melittin (a peptide from bee venom) interacted with Na,K-ATPase from rabbit kidney. In this study, a 43-kDa proteolytic fragment of Na,K-ATPase α-subunit interacting with the 67-kDa melittin-like protein was found. The α-subunit was hydrolyzed by(More)
By maintaining the Na(+) and K(+) transmembrane gradient mammalian Na,K-ATPase acts as a key regulator of neuronal electrotonic properties. Na,K-ATPase has an important role in synaptic transmission and memory formation. Accumulation of beta-amyloid (Aβ) at the early stages of Alzheimer's disease is accompanied by reduction of Na,K-ATPase functional(More)
Prolonged exposure of different epithelial cells (canine renal epithelial cells (MDCK), vascular endothelial cells from porcine aorta (PAEC), human umbilical vein endothelial cells (HUVEC), cervical adenocarcinoma (HeLa), as well as epithelial cells from colon carcinoma (Caco-2)) with ouabain or with other cardiotonic steroids was shown earlier to result in(More)
The decrease in the oxygen content of tissues, which is observed in a number of pathological processes, inevitably leads to damage. One of the main causes of cell damage and death in hypoxia is the failure of the systems that maintain the ionic balance. Na,K-ATPase is the main ion-transporting protein in the plasma membrane of animal cells, and its(More)
In rodents, ubiquitous α1-Na+, K+-ATPase is inhibited by ouabain and other cardiotonic steroids (CTS) at ~103-fold higher concentrations than those effective in other mammals. To examine the specific roles of the CTS-sensitive α1S- and CTS-resistant α1R-Na+, K+-ATPase isoforms, we compared the effects of ouabain on intracellular Na+ and K+ content, cell(More)
A comparison of sarcoplasmic reticulum (SR) preparations from skeletal muscles of ground squirrels Spermophilus undulatus, rats, and rabbits established that on the basis of protein yield and phospholipid/protein ratio these preparations are practically the same. Nevertheless, the specific activity of Ca-ATPase, the main protein component of SR membranes,(More)
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