Total and free Mg2+ contents in erythrocytes: a simple but still undisclosed cell model.
The concentration of intracellular free Mg2+ ([Mg2+]i) in erythrocytes, measured by means of 31P NMR and using a dissociation constant for MgATP of 38-50 microM, amounted to 0.2 mM [Mg2+]i in the erythrocytes of various species, was not significantly different and was independent of their total Mg2+ content. The more probable value of [Mg2+]i using the more realistic KD of Mg ATP or the null-point method may amount to 0.4 mM [Mg2+]i in erythrocytes is lower than the [Mg2+]i in nucleated mammalian cell types. The lower [Mg2+]i may be caused by a different regulation of Mg2+ influx and Mg2+ efflux by intracellular Mg2+ in erythroblasts. Free and reversibly bound Mg2+ represent a Mg2+ buffer. The main Mg2+-binding substances are ATP and 2,3-bisphosphoglycerate (2,3-BPG). Total Mg2+ content in the erythrocytes of various species is correlated to the concentrations of ATP and 2,3-BPG. The changed Mg2+ level in erythrocytes during deoxygenation, maturation, cold storage, in Mg2+ deficiency and in sickle cell anemia was reviewed.
Günther
Theodor
T
Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Institut für Molekularbiologie und Biochemie, Arnimallee 22, 14195 Berlin, Germany.
D019794:2,3-Diphosphoglycerate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000818:Animals; D002415:Cats; D002417:Cattle; D004285:Dogs; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000032:analysis* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods
D019794:2,3-Diphosphoglycerate; D000255:Adenosine Triphosphate; D008274:Magnesium