Effects of calcium on Na+,K (+) -ATPase isolated from human placenta
Mazzanti, L.; Rabini, R.A.; Cugini, A.M.; Zolese, G.
Biochemistry International 27(5): 847-852
1992
ISSN/ISBN: 0158-5231 PMID: 1329752 Document Number: 396629
It has been reported that Ca2+ can be either stimulatory or inhibitory of the activity of Na+,K(+)-ATPase obtained from different sources. The aim of the present work was to study the effect of increasing concentrations of Ca2+ on Na+,K(+)-ATPase activity and of placenta. The temperature dependence of Na+,K(+)-ATPase activity and of spectral parameters of a spin label paramagnetic maleimide) were also (MSL, 2,2,6,6-tetramethylpiperidin-1-oxyl-4-maleimide) were also investigated in absence and in presence of 2 mM Ca2+. Ca2+ affects positively the enzymatic activity and this effect is evident at all temperature tested. Maleimide spectral parameters are not affected by the presence of 2 mM Ca2+, showing that the microenvironments of SH groups are not modified following ion interactions.