English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Equilibrium and kinetic fluorescence methods have been used to characterize the interactions between K+ and the Ca(2+)-ATPase of skeletal-muscle sarcoplasmic reticulum. K+ shifts the E2-E1 equilibrium of the ATPase towards E1 and increases the rate of Ca2+ binding to the ATPase, as detected by changes in tryptophan fluorescence intensity, suggesting that K+ increases the rate of the E2-E1 transition. The data are consistent with binding of K+ at the inner Ca(2+)-binding site on the ATPase in competition with H+ and Mg2+, with a higher affinity in the E1 than in the E2 conformation. K+ has no effect on the affinity for Mg2+, as detected by changes in tryptophan fluorescence intensity; since it has been proposed that the changes in tryptophan fluorescence follow from binding to Mg2+ at the outer Ca(2+)-binding site, this suggests that K+ is unable to bind at the outer Ca(2+)-binding site. K+ increases the rate of dissociation of Ca2+ from the Ca(2+)-bound ATPase and reduces the effect of Mg2+ on the fluorescence intensity of the ATPase labelled with 4-(bromomethyl)-6,7-dimethoxycoumarin. It is suggested that these effects of K+ are the result of binding at a 'gating' site on the ATPase, in competition with binding of H+. Binding of K+ at the inner Ca(2+)-binding site and at the gating site account for the observed effects of K+ on the affinity of the ATPase for Ca2+.

Effects of K+ on the binding of Ca2+ to the Ca2+-ATPase of sarcoplasmic reticulum