NMR of Sodium-23 and Potassium-39 in Biological Systems

Civan, Mortimer M.; Shporer, M.

doi:10.1007/978-1-4615-6534-5_1

Cited by 65 publications

(56 citation statements)

References 94 publications

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“…The quadrupolar coupling constant of D 1.66 ð 10 6 rad s 1 was much higher than that obtained by James and Noggle (3 ð 10 5 rad s 1 ) 4 for 23 Na C in RNA, which has since been criticized as being artifactually low. 18 Note that the value we obtained was lower than the (4.8-7.6) ð10…”

Section: Simultaneous Fitting Of Relaxation Datacontrasting

confidence: 54%

Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS

Torres

Philp

Kemp-Harper

et al. 2004

Magnetic Reson in Chemistry

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Nuclear magnetic resonance provides several unique means of investigating the interactions between different inorganic ions and various macromolecules.23 Na is a quadrupolar nucleus, meaning that relaxation analysis of the various coherences allows the measurement of its binding to biological macromolecules. In this study, we analyzed the quadrupolar relaxation of 23 Na + longitudinal magnetization and single-and triple-quantum coherences in aqueous systems containing RNA, bovine serum albumin and sodium dodecyl sulfate micelles. The effectiveness of the James-Noggle method for determining binding constants was evaluated in these systems, and also the applicability of various 23 Na coherences in providing information on the extent and affinity of binding to the three different classes of biomolecules.

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Section: Simultaneous Fitting Of Relaxation Datacontrasting

confidence: 54%

Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS

Torres

Philp

Kemp-Harper

et al. 2004

Magnetic Reson in Chemistry

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“…More recently, Pike et al (8) have also observed small but significant discrepancies (5-10%) in the measurements of Na+ concentrations in RBC by the two methods. These differences are too small to ascribe to a first-order quadrupolar interaction (19). Possible mechanisms suggested by Pike et al (8) (24).…”

Section: Resultsmentioning

confidence: 94%

23Na and 39K NMR studies of ion transport in human erythrocytes.

Ogino¹,

Shulman²,

Avison³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

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Ion transport in human erythrocytes was studied by 23Na and 39K NMR with an anionic paramagnetic shift reagent, Dy(P3O10)7-. The intra-and extracellular 23Naand 39K NMR signals were well separated (over 10 ppm) at 5 mM concentration of the shift reagent. The NMR visibility of the intracellular Na' and K+ was determined to be 100% in human and duck erythrocytes. The intracellular ion concentrations were 8.1 + 0.8 mM Na+ (n = 7) and 110 ± 12 mM K+ (n = 4) for fresh human erythrocytes. The ouabain-sensitive net Na+ efflux was 1.75 ± 0.08 mmol/hr per liter of cells at 370C (n = 3). The gramicidin-induced ion transport in human erythrocytes was also studied by 23Na and 39K NMR or by simultaneous measurements of 23Na NMR and a V-selective electrode. The time courses of the Na+ and K+ transport induced by the ionophore were biphasic. The initial rapid fluxes were due to an exchange of Na+ for K+, which were found to occur with a 1:1 stoichiometry. The subsequent slow components were the net Na+ and K+ effluxes rate-limited by the Cl-permeability and accompanied by a reduction in cell volume. The Cl-permeability determined from the NMR measurements of these slow fluxes was 3.2 + 0.5 x 10-8 cm/sec at 250C (n = 4).Concentration gradients of Na+ and K+ across the erythrocyte (RBC) membrane are primarily maintained by an active transport of Na+ and K+ by the Na+,K+-pump (1). The kinetic properties of the Na+,K+-pump have been extensively studied in RBC. Alterations in Na+ fluxes with resultant abnormal intracellular Na+ concentration in RBC have been suggested to exist in a variety of disease processes, such as essential hypertension (2), affective disorders (3), myotonic dystrophy (4), and hyperthyroidism (5). Conventional methods of analysis for intracellular ions such as flame photometry and radioisotope tracer techniques have the disadvantage of requiring time-consuming destructive methods to achieve physical separation of intraand extracellular compartments. Furthermore, there are uncertainties associated with the possibility of nonspecific binding of ions to the cell membrane and of ion fluxes occurring during the separation procedure. Clearly, a nondestructive and noninvasive method would be welcome.NMR spectroscopy offers such an approach. The recent development of anionic paramagnetic shift reagents (SRs) (6, 7) has made it possible to resolve the intra-and extracellular NMR signals of 23Na and 39K in cells and tissues. This approach has been applied to measure intracellular Na+ (7,8) and K+ (9) concentrations and to study the physical state of intracellular Na+ in RBC (10). However, no studies of ion transport in RBC have been reported, even though the NMR method would have advantages in the study of ion fluxes (11).The present study demonstrates the suitability of NMR spectroscopy with the paramagnetic SR Dy(P3010)7-for measuring Na' and K+ fluxes as well as ion concentrations in human RBC. EXPERIMENTAL Blood was drawn from healthy donors into a syringe containing sodium heparin (10 units/ml). The RBC wer...

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“…DISCUSSION Because 39K is a nucleus of low NMR sensitivity, few 39K NMR studies of biological systems have been reported (ref. 17 and references cited therein). The improvement in sensitivity of a home-built solenoidal coil probe allowed us to follow time courses of K+ transport with a time resolution of 1 min.…”

Section: Resultsmentioning

confidence: 99%

“…After the first observation Of 23Nain NMR signals by Cope (19), several determinations of NMR visibility of Na+ were reported, with the fractions detected ranging from 25% to 50% (17). Part of these variations may arise from the difficulties in [10][11][12][13][14][15][16] ,umol/ml of cell water in the absence and in the presence, respectively, of ethanol.…”

Section: Resultsmentioning

confidence: 99%

39K, 23Na, and 31P NMR studies of ion transport in Saccharomyces cerevisiae.

Ogino¹,

Hollander²,

Shulman³

1983

Proc. Natl. Acad. Sci. U.S.A.

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The relationship between efflux and influx of K+, Na', and intracellular pH (pH' ) in yeast cells upon energizing by oxygenation was studied by using the noninvasive technique of -9K, DNa, and 31P NMR.spectroscopy. By introducing an anionic paramagnetic shift reagent, Dy3+(P3O)2i, into the medium, NMR'signals of intra-and extracellular K+ and Na+ could be resolved, enabling us to study ion transport processes by NMR. Measurements showed that 40% of the intracellular K+ In this work we studied by the noninvasive technique of NMR spectroscopy the relationship between efflux and influx of Na', K+, and pHin when energizing yeast cells by oxygenation. With the aid of a home-built solenoidal coil probe and an anionic shift reagent, we now can follow time courses of K+ with a time resolution of 1 min in yeast suspensions. In separate experiments under the same conditions, Na+ transport and pHin could be followed-on one sample by using a probe double-tuned for 23Na and 31P and switching back and forth every 1 min. EXPERIMENTALThe Saccharomyces cerevisiae strain NCYC 239 was grown at 30°C for 24 hr in 2% Bacto-peptone, 1% yeast extract, and 2% glucose. Before harvest, the cultures were chilled to 4°C, after which the cells were collected by low-speed centrifugation. The cells were washed twice and-resuspended to a pellet/medium density of .1:2 in a resuspension medium consisting of 0.85 g of KH2PO4, 0.15 In all experiments, gas was bubbled through the suspension. In aerobic experiments, a 95% 02/5% CO2 was used; in anAbbreviations: pHm, intracellular pH; Na:,t and -Kout, extracellular Na+ and K+; Na+ and K,+, intracellular Na+ and K+. 5185 The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisenent" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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NMR of Sodium-23 and Potassium-39 in Biological Systems

Cited by 65 publications

References 94 publications

Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS

Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS

23Na and 39K NMR studies of ion transport in human erythrocytes.

39K, 23Na, and 31P NMR studies of ion transport in Saccharomyces cerevisiae.

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NMR of Sodium-23 and Potassium-39 in Biological Systems

Cited by 65 publications

References 94 publications

Determination of Na+ binding parameters by relaxation analysis of selected 23Na NMR coherences: RNA, BSA and SDS

Determination of Na+ binding parameters by relaxation analysis of selected 23Na NMR coherences: RNA, BSA and SDS

23Na and 39K NMR studies of ion transport in human erythrocytes.

39K, 23Na, and 31P NMR studies of ion transport in Saccharomyces cerevisiae.

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Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS

Determination of Na⁺ binding parameters by relaxation analysis of selected ²³Na NMR coherences: RNA, BSA and SDS