Abstract
Hypophosphorus acid has a single pKa of 1.1 and at physiological pH values it is therefore present almost entirely as the univalent hypophosphite ion. When added to a red cell suspension the ion crosses the cell membrane rapidly, via the anion exchange protein, and the intra- and extracellular populations of the ion give rise to separate 31P NMR resonances. From a single 31P NMR spectrum it was possible to determine the relative amounts of hypophosphite in the intra- and extracellular compartments and thereby estimate the corresponding concentrations. The ratio of intracellular to extracellular hypophosphite concentration was independent of the total hypophosphite concentration for cells suspended in NaCl solutions and was independent of hematocrit. The hypophosphite distribution ratio increased as extracellular NaCl was replaced iso-osmotically with citrate or sucrose, through it remained very similar to the corresponding hydrogen ion distribution ratio. Incorporation of the hypophosphite distribution ratio into the Nernst equation yielded an estimate of the membrane potential. For cells suspended in NaCl solutions the estimated potential was consistently around -10 mV.
Full text
PDF






Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bashford C. L., Smith J. C. The use of optical probes to monitor membrane potential. Methods Enzymol. 1979;55:569–586. doi: 10.1016/0076-6879(79)55067-8. [DOI] [PubMed] [Google Scholar]
- DeFronzo M., Gillies R. J. Characterization of methylphosphonate as a 31P NMR pH indicator. J Biol Chem. 1987 Aug 15;262(23):11032–11037. [PubMed] [Google Scholar]
- Fabry M. E., San George R. C. Effect of magnetic susceptibility on nuclear magnetic resonance signals arising from red cells: a warning. Biochemistry. 1983 Aug 16;22(17):4119–4125. doi: 10.1021/bi00286a020. [DOI] [PubMed] [Google Scholar]
- Gary-Bobo C. M., Solomon A. K. Properties of hemoglobin solutions in red cells. J Gen Physiol. 1968 Nov;52(5):825–853. doi: 10.1085/jgp.52.5.825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldman D. E. POTENTIAL, IMPEDANCE, AND RECTIFICATION IN MEMBRANES. J Gen Physiol. 1943 Sep 20;27(1):37–60. doi: 10.1085/jgp.27.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., KATZ B. The effect of sodium ions on the electrical activity of giant axon of the squid. J Physiol. 1949 Mar 1;108(1):37–77. doi: 10.1113/jphysiol.1949.sp004310. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hladky S. B., Rink T. J. pH Changes in human erythrocytes reported by 3,3' dipropylthia-dicarbocyanine, diS-C3-(5) [proceedings]. J Physiol. 1976 Dec;263(1):213P–214P. [PubMed] [Google Scholar]
- Hoffman J. F., Kaplan J. H., Callahan T. J. The Na:K pump in red cells is electrogenic. Fed Proc. 1979 Oct;38(11):2440–2441. [PubMed] [Google Scholar]
- Hoffman J. F., Laris P. C. Determination of membrane potentials in human and Amphiuma red blood cells by means of fluorescent probe. J Physiol. 1974 Jun;239(3):519–552. doi: 10.1113/jphysiol.1974.sp010581. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kirk K., Kuchel P. W. The contribution of magnetic susceptibility effects to transmembrane chemical shift differences in the 31P NMR spectra of oxygenated erythrocyte suspensions. J Biol Chem. 1988 Jan 5;263(1):130–134. [PubMed] [Google Scholar]
- Knauf P. A., Fuhrmann G. F., Rothstein S., Rothstein A. The relationship between anion exchange and net anion flow across the human red blood cell membrane. J Gen Physiol. 1977 Mar;69(3):363–386. doi: 10.1085/jgp.69.3.363. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Labotka R. J., Kleps R. A. A phosphate-analogue probe of red cell pH using phosphorus-31 nuclear magnetic resonance. Biochemistry. 1983 Dec 20;22(26):6089–6095. doi: 10.1021/bi00295a008. [DOI] [PubMed] [Google Scholar]
- Labotka R. J. Measurement of intracellular pH and deoxyhemoglobin concentration in deoxygenated erythrocytes by phosphorus-31 nuclear magnetic resonance. Biochemistry. 1984 Nov 6;23(23):5549–5555. doi: 10.1021/bi00318a026. [DOI] [PubMed] [Google Scholar]
- Labotka R. J., Omachi A. Erythrocyte anion transport of phosphate analogs. J Biol Chem. 1987 Jan 5;262(1):305–311. [PubMed] [Google Scholar]
- Petersen A., Jacobsen J. P., Hørder M. 31P NMR measurements of intracellular pH in erythrocytes: direct comparison with measurements using freeze-thaw and investigation into the influence of ionic strength and Mg2+. Magn Reson Med. 1987 Apr;4(4):341–350. doi: 10.1002/mrm.1910040405. [DOI] [PubMed] [Google Scholar]
- Rottenberg H. The measurement of membrane potential and deltapH in cells, organelles, and vesicles. Methods Enzymol. 1979;55:547–569. doi: 10.1016/0076-6879(79)55066-6. [DOI] [PubMed] [Google Scholar]
- SAVITZ D., SIDEL V. W., SOLOMON A. K. OSMOTIC PROPERTIES OF HUMAN RED CELLS. J Gen Physiol. 1964 Sep;48:79–94. doi: 10.1085/jgp.48.1.79. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sims P. J., Waggoner A. S., Wang C. H., Hoffman J. F. Studies on the mechanism by which cyanine dyes measure membrane potential in red blood cells and phosphatidylcholine vesicles. Biochemistry. 1974 Jul 30;13(16):3315–3330. doi: 10.1021/bi00713a022. [DOI] [PubMed] [Google Scholar]
- Stewart I. M., Chapman B. E., Kirk K., Kuchel P. W., Lovric V. A., Raftos J. E. Intracellular pH in stored erythrocytes. Refinement and further characterisation of the 31P-NMR methylphosphonate procedure. Biochim Biophys Acta. 1986 Jan 23;885(1):23–33. doi: 10.1016/0167-4889(86)90034-0. [DOI] [PubMed] [Google Scholar]
- Thoma W. J., Steiert J. G., Crawford R. L., Uğurbil K. pH measurements by 31p NMR in bacterial suspensions using phenyl phosphonate as a probe. Biochem Biophys Res Commun. 1986 Aug 14;138(3):1106–1109. doi: 10.1016/s0006-291x(86)80396-5. [DOI] [PubMed] [Google Scholar]
- Warburg E. J. Studies on Carbonic Acid Compounds and Hydrogen Ion Activities in Blood and Salt Solutions. A Contribution to the Theory of the Equation of Lawrence J. Henderson and K. A. Hasselbach: CHAP. XII. Biochem J. 1922;16(2):307–340. doi: 10.1042/bj0160307. [DOI] [PMC free article] [PubMed] [Google Scholar]
