Mechanism of the rate-determining step of the Na+,K+-ATPase pump cycle

Cite This

Files in this item

Checksum: MD5:09c8c29221f48c7653c24c0cefa78731

HUMPHREY, Paul A., Christian LÜPFERT, Hans-Jürgen APELL, Flemming CORNELIUS, Ronald J. CLARKE, 2002. Mechanism of the rate-determining step of the Na+,K+-ATPase pump cycle. In: Biochemistry. 41(30), pp. 9496-9507. ISSN 0006-2960. eISSN 1520-4995

@article{Humphrey2002Mecha-6865, title={Mechanism of the rate-determining step of the Na+,K+-ATPase pump cycle}, year={2002}, number={30}, volume={41}, issn={0006-2960}, journal={Biochemistry}, pages={9496--9507}, author={Humphrey, Paul A. and Lüpfert, Christian and Apell, Hans-Jürgen and Cornelius, Flemming and Clarke, Ronald J.} }

<rdf:RDF xmlns:dcterms="" xmlns:dc="" xmlns:rdf="" xmlns:bibo="" xmlns:dspace="" xmlns:foaf="" xmlns:void="" xmlns:xsd="" > <rdf:Description rdf:about=""> <dc:contributor>Humphrey, Paul A.</dc:contributor> <dc:contributor>Clarke, Ronald J.</dc:contributor> <dcterms:abstract xml:lang="deu">The kinetics of the E2 E1 conformational change of unphosphorylated Na+,K+-ATPase from rabbit kidney and shark rectal gland were investigated via the stopped-flow technique using the fluorescent label RH421 (pH 7.4, 24 C). The enzyme was pre-equilibrated in a solution containing 25 mM histidine and 0.1 mM EDTA to stabilize initially the E2 conformation. When rabbit kidney enzyme was mixed with NaCl alone, tris ATP alone or NaCl, and tris ATP simultaneously, a fluorescence decrease was observed. The reciprocal relaxation time, 1/r of the fluorescent transient was found to increase with increasing NaCl concentration and reached a saturating value in the presence of 1 mM tris ATP of 54 ± 3 s-1 in the case of rabbit kidney enzyme. The experimental behavior could be described by a binding of Na+ to the enzyme in the E2 state with a dissociation constant of 31 ± 7 mM, which induces a subsequent rate-limiting conformational change to the E1 state. Similar behavior, but with a decreased saturating value of 1/, was found when NaCl was replaced by choline chloride. Analogous experiments performed with enzyme from shark rectal gland showed similar effects, but with a significantly lower amplitude of the fluorescence change and a higher saturating value of 1/ for both the NaCl and choline chloride titrations. The results suggest that Na+ ions or salt in general play a regulatory role, similar to that of ATP, in enhancing the rate of the rate-limiting E2 E1 conformational transition by interaction with the E2 state.</dcterms:abstract> <dcterms:isPartOf rdf:resource=""/> <dcterms:hasPart rdf:resource=""/> <dc:rights>Attribution-NonCommercial-NoDerivs 2.0 Generic</dc:rights> <foaf:homepage rdf:resource="http://localhost:8080/jspui"/> <dcterms:rights rdf:resource=""/> <dc:creator>Lüpfert, Christian</dc:creator> <dc:contributor>Lüpfert, Christian</dc:contributor> <dc:contributor>Apell, Hans-Jürgen</dc:contributor> <dc:creator>Apell, Hans-Jürgen</dc:creator> <dc:creator>Clarke, Ronald J.</dc:creator> <dcterms:issued>2002</dcterms:issued> <dc:date rdf:datatype="">2011-03-24T17:29:45Z</dc:date> <dc:language>eng</dc:language> <dspace:isPartOfCollection rdf:resource=""/> <dc:contributor>Cornelius, Flemming</dc:contributor> <dc:creator>Cornelius, Flemming</dc:creator> <dspace:hasBitstream rdf:resource=""/> <dc:creator>Humphrey, Paul A.</dc:creator> <dc:format>application/pdf</dc:format> <bibo:uri rdf:resource=""/> <dcterms:title>Mechanism of the rate-determining step of the Na+,K+-ATPase pump cycle</dcterms:title> <void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/> <dcterms:bibliographicCitation>First publ. in: Biochemistry ; 41 (2002). - S. 9496-9507</dcterms:bibliographicCitation> </rdf:Description> </rdf:RDF>

Downloads since Oct 1, 2014 (Information about access statistics)

Mechanism_of_the_rate_determining_step_of_the.pdf 283

This item appears in the following Collection(s)

Attribution-NonCommercial-NoDerivs 2.0 Generic Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 2.0 Generic

Search KOPS


My Account