Dependence on membrane lipids of the effect of vanadate on calcium and ATP binding to sarcoplasmic reticulum ATPase.

The affinity of the sarcoplasmic reticulum transport ATPase for calcium and ATP is not affected by lipid deprivation 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.