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'Sarcoplasmic Reticulum ATPase' in keywords
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1989 (1)
1984 (1)
1Author    Pankaj Medda, Wilhelm HasselbachRequires cookie*
 Title    Dependence on Membrane Lipids of the Effect of Vanadate on Calcium and ATP Binding to Sarcoplasmic Reticulum ATPase  
 Abstract    The affinity of the sarcoplasmic reticulum transport ATPase for calcium and ATP is not affected by lipid depriviation while vanadate binding is completely abolished. Lipid substitution restores vanadate binding as well as the vanadate induced disappearance of the enzyme's high affinity calcium and nucleotide binding sites. Nucleotide binding is simultaneously restored with the displacement of vanadate from the enzyme following the occupation of its low affinity calcium binding sites. 
  Reference    Z. Naturforsch. 39c, 1137—1140 (1984); received August 31 1984 
  Published    1984 
  Keywords    Sarcoplasmic Reticulum ATPase, Vanadate, Calcium, Adenosinetriphosphate 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-1137.pdf 
 Identifier    ZNC-1984-39c-1137 
 Volume    39 
2Author    Elisabeth Fassold, Wilhelm Hasselbach, Bernd KüchlerRequires cookie*
 Title    Effect of Non-Solubilizing SDS Concentrations on High Affinity Ca2+ Binding and Steady State Phosphorylation by Inorganic Phosphate of the Sarcoplasmic Reticulum ATPase  
 Abstract    In this investigation low, non-solubilizing concentrations of the strong anionic detergent SDS were used to perturbate the interaction of Ca2+ and P, with their respective binding domains on the sarcoplasmic reticulum Ca-transport ATPase. Rising SDS concentrations produce a two-step decline of Ca2+-dependent ATP hydrolysis. At pH 6.15, SDS differently affects high affinity Ca2+ binding and phosphorylation by inorganic phosphate and releases the "mutual exclusion" of these two ligand binding steps. The degree of uncoupling is considerably more pronounced in the presence of 20% Me2SO. The reduction of Ca2+ binding by SDS is demonstrated to be a result of decreased affinity of one of the two specific high affinity binding sites and of perturbation of their cooperative inter­ action. Higher SDS partially restores the original high Ca2f affinity but not the cooperativity of binding. Phosphorylation exhibits a higher SDS sensitivity than Ca2+ binding: Increasing SDS competitively inhibits and then completely abolishes phosphoenzyme formation. Thus. SDS binds to the phosphorylation domain, evidently involving the Lys352 residue of the ATPase molecule; this is accompanied by a more unspecific concentration-dependent SDS effect, probably mediated by hydrophobic force, which, finally, suppresses phosphorylation. Me2SO does neither qualitatively affect the SDS-dependent chemical properties of the vesicular material nor the SDS-dependent perturbation of the investigated reaction steps. 
  Reference    Z. Naturforsch. 44c, 139 (1989); received November 28 1988 
  Published    1989 
  Keywords    Sarcoplasmic Reticulum ATPase, Calcium Binding, Phosphorylation, SDS 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0139.pdf 
 Identifier    ZNC-1989-44c-0139 
 Volume    44