Transmembrane Ca2+ gradient-mediated modulation of sarcoplasmic reticumul Ca2+-ATPase

Yaping Tu, F. Y. Yang

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Ca2+-ATPase from skeletal muscle sarcoplasmic reticulum was reconstituted into liposomes with (100-1000 fold) or without transmembrane Ca2+ gradient. The highest enzyme activity and Ca2+ uptake were observed in the vesicles without transmembrane Ca2+ gradient. If there existed transmembrane Ca2+ gradient, no matter what the direction was, a lower activity would appear. Dissipation of transmembrane Ca2+ gradient by A23187 could lead to a change in enzyme activity of incorporated Ca2+-ATPase. A concomitant change of lipid fluidity of proteoliposomes with that of enzyme activity and Ca2+ uptake was observed. The inhibition of Ca2+-ATPase by the transmembrane Ca2+ gradient could be observed in the PC-PE vesicles, but not in the PS-PE or PG-PE proteoliposomes.

Original languageEnglish
Pages (from-to)561-568
Number of pages8
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - 1993
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Biophysics
  • Molecular Biology

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