Asymmetric effects of divalent cations and protons on active Ca2+ efflux and Ca2+-ATPase in intact red blood cells

The Journal of Membrane Biology
Y H Xu, B D Roufogalis


The influence of the asymmetric addition of various divalent cations and protons on the properties of active Ca2+ transport have been examined in intact human red blood cells. Active Ca2+ efflux was determined from the initial rate of 45Ca2+ loss after CoCl2 was added to block Ca2+ loading via the ionophore A23187. Ca2+-ATPase activity was measured as phosphate production over 5 min in cells equilibrated with EGTA-buffered free Ca2+ in the presence of A23187. The apparent Ca affinity of active Ca2+ efflux (K0.5 = 30-40 mumol/liter cells) was significantly lower than that measured by the Ca2+-ATPase assay (K0.5 = 0.4 microM). Possible reasons for this apparent difference are considered. Both active Ca2+ efflux and Ca2+-ATPase activity were reduced to less than 5% of maximal levels (20 mmol/liter in Mg2+-depleted cells, and completely restored by reintroduction of intracellular Mg2+. Active Ca2+ efflux was inhibited almost completely by raising external CaCl2 (but not MgCl2) to 20 mM, probably by interaction of Ca2+ at the externally oriented E2P conformation of the pump. Cd2+ was more potent than Ca2+ in this inhibition, while Mn2+ was less potent and 10 mM Ba2+ was without effect. A Ca2+: proton exchange mechanism for...Continue Reading


Apr 28, 1978·Annals of the New York Academy of Sciences·H J Schatzmann, H Bürgin
Nov 15, 1979·Analytical Biochemistry·P A LanzettaO A Candia
Jan 18, 1979·Nature·S Mualem, S J Karlish
Jul 24, 1975·The Journal of Membrane Biology·A F Rega, P J Garrahan
Aug 1, 1975·The Journal of Physiology·M Dalmark
Sep 18, 1987·Biochimica Et Biophysica Acta·G DagherA Khefif
Jan 1, 1989·Methods in Enzymology·V L Lew, J Garcia-Sancho
Dec 16, 1986·Biochimica Et Biophysica Acta·A J CarideP J Garrahan
Jan 16, 1986·Biochimica Et Biophysica Acta·A VillaloboB D Roufogalis
Jan 1, 1986·The Journal of Membrane Biology·N Escobales, M Canessa
Jun 27, 1985·Biochimica Et Biophysica Acta·R B KratjeA F Rega
May 1, 1971·The Journal of Physiology·P J Romero, R Whittam
May 7, 1982·Biochimica Et Biophysica Acta·S Muallem, S J Karlish
Dec 31, 1982·Biochimica Et Biophysica Acta·E Carafoli, M Zurini
May 5, 1983·Biochimica Et Biophysica Acta·O ScharffU Skibsted
Oct 1, 1983·The Journal of Physiology·A M Brown, V L Lew
Aug 1, 1980·The Journal of Physiology·P W Flatman, V L Lew
Jan 1, 1982·Journal of Inherited Metabolic Disease·F A HommesB A Gordon


Aug 1, 1991·Journal of Cellular Biochemistry·Y H XuB D Roufogalis
Oct 3, 2002·The Journal of General Physiology·M A Milanick, Krista L Arnett
Apr 1, 1999·Archives of Physiology and Biochemistry·O A Gende
Apr 29, 1992·Biochimica Et Biophysica Acta·L WuF F Vincenzi
May 6, 2008·Cellular Physiology and Biochemistry : International Journal of Experimental Cellular Physiology, Biochemistry, and Pharmacology·Saisudha KokaFlorian Lang
May 20, 2011·Journal of Neurophysiology·Sunil A Desai, Gregory A Lnenicka
May 4, 2000·American Journal of Physiology. Cell Physiology·W XuM A Milanick

Related Concepts

Ca(2+)-Transporting ATPase
Cations, Divalent
Hydrogen-Ion Concentration
Resting Potentials

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Synthetic Genetic Array Analysis

Synthetic genetic arrays allow the systematic examination of genetic interactions. Here is the latest research focusing on synthetic genetic arrays and their analyses.

Congenital Hyperinsulinism

Congenital hyperinsulinism is caused by genetic mutations resulting in excess insulin secretion from beta cells of the pancreas. Here is the latest research.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Epigenetic Memory

Epigenetic memory refers to the heritable genetic changes that are not explained by the DNA sequence. Find the latest research on epigenetic memory here.

Cell Atlas of the Human Eye

Constructing a cell atlas of the human eye will require transcriptomic and histologic analysis over the lifespan. This understanding will aid in the study of development and disease. Find the latest research pertaining to the Cell Atlas of the Human Eye here.

Femoral Neoplasms

Femoral Neoplasms are bone tumors that arise in the femur. Discover the latest research on femoral neoplasms here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.