Competition between Li+ and Mg2+ for ATP in human erythrocytes. A 31P NMR and optical spectroscopy study.
We have investigated the influence of Li+ on free intracellular Mg2+ concentration in human erythrocytes by 31P NMR and optical absorbance spectroscopies. In red cells loaded with 3 mM intracellular Li+, the chemical shift separation between the alpha- and beta-phosphate resonances of MgATP2- was approx. 0.9 ppm larger than that observed in Li+-free red cells. By analyzing the interaction of each red cell component with Mg2+ and Li+, we found that Mg2+ is displaced in part from MgATP2- upon addition of Li+ and that the released Mg2+ is bound to the red cell membrane causing an overall decrease in free intracellular Mg2+ concentration.
Ramasamy
R
R
Department of Chemistry, Loyola University of Chicago, IL 60626.
de Freitas
D M
DM
D000255:Adenosine Triphosphate / Q000097:blood*; D001667:Binding, Competitive; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D008094:Lithium / Q000097:blood*; D008274:Magnesium / Q000097:blood*; D009682:Magnetic Resonance Spectroscopy; D013053:Spectrophotometry
D000255:Adenosine Triphosphate; D008094:Lithium; D008274:Magnesium