Active Transport of Na<sup>+</sup> and K<sup>+</sup> through Animal Cell Membranes

Schoner, Wilhelm

doi:10.1002/anie.197108821

Cited by 20 publications

(5 citation statements)

References 151 publications

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“…The reaction of DCCD with the Na,K-and H,K-ATPases and inhibition of activity by DCCD demonstrate a role for carboxylic acids in the membrane domain in transport by these enzymes (3,4,38,39). Site-directed mutations of the sarcoplasmic reticular Ca 2ϩ -ATPase and the Na,K-ATPase that affect ion binding place the carboxylic acids of those pumps in this TM5/ TM6 region in the membrane domain (40,41).…”

Section: Discussionmentioning

confidence: 99%

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Besancon

Simon²,

Sachs

et al. 1997

Journal of Biological Chemistry

245

178

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The vesicular gastric H,K-ATPase catalyzes an electroneutral H for K exchange allowing acidification of the intravesicular space. There is a total of 28 cysteines present in the ␣ subunit of the gastric H,K-ATPase, of which 10 are found in the predicted transmembrane segments and their connecting loop, and 9 are present in the ␤ subunit, of which 6 are disulfide-linked. To determine which of these was accessible to extracytoplasmic attack, the enzyme was inhibited by four different sub- , under acid transporting conditions. All of these compounds are weak bases that accumulate in the acidic space generated by the pump and undergo an acid catalyzed rearrangement to a cationic sulfenamide, which forms disulfides with accessible cysteines. The relative rates of acid activation of these compounds corresponded to the relative rates of inhibition of ATPase activity and acid transport. Fragmentation of the enzyme by trypsin followed by SDS-polyacrylamide gel electrophoresis showed that omeprazole bound covalently to one of the two cysteines in the domains containing the fifth and sixth transmembrane segments and their extracytoplasmic loop and to cysteine 892 in the loop between the seventh and eighth transmembrane segments, but inhibition correlated with the reaction with cysteines in the fifth and sixth domain. Lansoprazole bound to the cysteines in these two domains as well as to cysteine 321 toward the extracytoplasmic end of the third transmembrane segments. Pantoprazole bound only to either cysteine 813 or 822 in the fifth and sixth transmembrane region. The inhibition of Rabeprazole correlated also with its binding to this part of the protein, but this compound continued to bind after full inhibition, eventually binding also to cysteines 321 and 892. No binding was found to any of the cysteines in the seventh to tenth transmembrane segments. Thermolysin digestion of the isolated omeprazole-labeled fifth and sixth transmembrane pair showed that cysteine 813 was the site of labeling. It is concluded that binding of these sided reagents to cysteine 813 in the loop between transmembrane (TM)5 and TM6 is sufficient for inhibition of ATPase activity and acid transport by the gastric acid pump. Of the 10 cysteines present in the membrane and extracytoplasmic domain, only three are exposed sufficiently to allow reactivity with these cationic thiol reagents. The binding to cysteine 813 defines the location of the extracytoplasmic loop between TM5 and TM6 and places the carboxylic acids 820 and 824 conserved between the gastric H,K-and the Na,K-ATPases in TM6, consistent with their assumed role in cation binding.

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Section: Discussionmentioning

confidence: 99%

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Besancon

Simon²,

Sachs

et al. 1997

Journal of Biological Chemistry

245

178

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“…This is perhaps reasonable in light of the usual formulation of the reaction sequence [3] whereby the enzyme is first phosphorylated in a Na ÷and Mg2+-dependent step, followed by a K+-dependent dephosphorylation (with high K+-affinity following phosphorylation). In contrast to schemes proposing cyclical conversion of Na ÷-and K ÷-sites with the reaction sequence [1][2][3] the continued existence of Na +-and K+-sites throughout the ligand states supports formulations of separate sites for these ions [1,4,7,8,13].…”

Section: Additionmentioning

confidence: 96%

“…

Since the (Na t + K÷)-dependent ATPase represents an essential part of, if not the entire, mechanism for transporting Na + andK + across cell membranes [1][2][3], the nature of the activation of the enzyme by these same ions seems particularly crucial. Recently, the affinity of the ATPase for K + was investigated by measuring the K+-dependent inactivation of the enzyme by Be 2+ [4].

…”

mentioning

confidence: 99%

Affinity of the (Na⁺ + K⁺)‐dependent ATPase for Na⁺ measured by NA⁺‐modified enzyme inactivation

Robinson

1974

FEBS Letters

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“…The efficient detection of trace metal ions has attracted a great deal of attention because of their environmental and biological relevance 13–22. Alkaline and alkaline earth metals play diverse roles in the human body as well as biological activities, such as structural and catalytic cofactors, neural transmitters, chemical signal transduction, and modulators, etc 23–25.…”

Section: Introductionmentioning

confidence: 99%

“…28–31. Especially, many sensing schemes for potassium have been proposed due to biological importance of K + ions 20, 32. Potassium plays a major role in cellular biochemical reactions and energy metabolism.…”

Section: Introductionmentioning

confidence: 99%

Ratiometric Fluorescent Ion Detection in Water with High Sensitivity via Aggregation‐Mediated Fluorescence Resonance Energy Transfer Using a Conjugated Polyelectrolyte as an Optical Platform

Kim

Lee

et al. 2013

Macromol. Rapid Commun.

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A cationic conjugated polyelectrolyte was designed and synthesized based on poly(fluorene-co-phenylene) containing 5 mol% benzothiadiazole (BT) as a low energy trap and 15-crown-5 as a recognizing group for potassium ions. A potassium ion can form a sandwich-type 2:1 Lewis acid-based complex with 15-crown-5, to cause the intermolecular aggregation of polymers. This facilitates inter-chain fluorescence resonance energy transfer (FRET) to a low-energy BT segment, resulting in fluorescent signal amplification, even at dilute analyte concentrations. Highly sensitive and selective detection of K(+) ions was demonstrated in water. The linear response of ratiometric fluorescent signal as a function of [K(+) ] allows K(+) quantification in a range of nanomolar concentrations with a detection limit of ≈0.7 × 10(-9) M.

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Active Transport of Na⁺ and K⁺ through Animal Cell Membranes

Cited by 20 publications

References 151 publications

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Affinity of the (Na⁺ + K⁺)‐dependent ATPase for Na⁺ measured by NA⁺‐modified enzyme inactivation

Ratiometric Fluorescent Ion Detection in Water with High Sensitivity via Aggregation‐Mediated Fluorescence Resonance Energy Transfer Using a Conjugated Polyelectrolyte as an Optical Platform

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Active Transport of Na+ and K+ through Animal Cell Membranes

Cited by 20 publications

References 151 publications

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Sites of Reaction of the Gastric H,K-ATPase with Extracytoplasmic Thiol Reagents

Affinity of the (Na+ + K+)‐dependent ATPase for Na+ measured by NA+‐modified enzyme inactivation

Ratiometric Fluorescent Ion Detection in Water with High Sensitivity via Aggregation‐Mediated Fluorescence Resonance Energy Transfer Using a Conjugated Polyelectrolyte as an Optical Platform

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Product

Resources

About

Active Transport of Na⁺ and K⁺ through Animal Cell Membranes

Affinity of the (Na⁺ + K⁺)‐dependent ATPase for Na⁺ measured by NA⁺‐modified enzyme inactivation