A fresh approach to the calculation of signal-to-noise ratio, using the Principle of Reciprocity, is formulated. The method is shown, for a solenoidal receiving coil, to give the same results as the traditional method of calculation, but its advantage lies in its ability to predict the ratio for other coil configurations. Particular attention is paid to the poor performance of a saddle-shaped (or Helmholtz) coil. Some of the practical problems involved are also discussed, including the error of matching the probe to the input impedance of the preamplifier.

A conventional field-frequency lock requires excellent phase stability (typically ±1°) and negligible change of leakage (<2% of the signal) if the lock is to be maintained to an accuracy of one part in 109, a typical homogeneity for a high-resolution magnet. Such specifications are very difficult to achieve under variable temperature conditions. Another drawback of a conventional lock is that it tends to interfere with the main signal, giving sidebands in the spectrum, if the two Larmor frequencies are at all close to one another. Provided only long-term stability is required, as is normally the case with a superconducting system, a lock having none of the above disadvantages may be constructed on the principle of a phase-locked loop, using a deuterium free induction decay to monitor the magnetic field. Such a lock is capable of “pulling in” in milliseconds from a considerable error in deuterium frequency (e.g., 30 Hz) while maintaining the desired long-term stability. The device has been successfully used with concentrations of heavy water as small as 0.1% of the sample volume.

1. Proton magnetic resonance spectra at 270 MHz of polymyxin B, a cationic oligopeptide antibiotic, show the influence of the inorganic counteranion present in solution. 2. Hydrogen-deuterium exchange rates for the amide protons are of two types, depending on whether the anion is monovalent or polyvalent. Polyvalent anions catalyse the acid-catalysed reaction more than the monovalent anions. 3. The structure in solution was monitored using the proton signals of the amides, the phenylalanine aromatic protons, and the leucine methyl and gamma-CH protons in several polymyxin salts. The temperature coefficients of the chemical shifts of the N-H protons are used to identify two beta turns in the cyclic ring of polymyxin B. The variation in chemical shift of the N-H protons, the aromatic protons and the leucine protons are correlated with anionic size and electronegativity.

Conference Article| February 01 1976 A New Approach to Metabolite Compartmentation in Muscle P. JOHN SEELEY; P. JOHN SEELEY 1Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K. Search for other works by this author on: This Site PubMed Google Scholar STEPHEN J. W. BUSBY; STEPHEN J. W. BUSBY 2Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K. Search for other works by this author on: This Site PubMed Google Scholar DAVID G. GADIAN; DAVID G. GADIAN 3Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K. Search for other works by this author on: This Site PubMed Google Scholar GEORGE K. RADDA; GEORGE K. RADDA 4Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K. Search for other works by this author on: This Site PubMed Google Scholar REX E. RICHARDS REX E. RICHARDS 5Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1976) 4 (1): 62–64. https://doi.org/10.1042/bst0040062 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation P. JOHN SEELEY, STEPHEN J. W. BUSBY, DAVID G. GADIAN, GEORGE K. RADDA, REX E. RICHARDS; A New Approach to Metabolite Compartmentation in Muscle. Biochem Soc Trans 1 February 1976; 4 (1): 62–64. doi: https://doi.org/10.1042/bst0040062 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1976 Biochemical Society1976 Article PDF first page preview Close Modal You do not currently have access to this content.

A transmit-receive system with a short recovery time and excellent isolation has been developed. The system operates in conjunction with an ENI Model 3200L broadband amplifier and a spin-lock NMR pulse spectrometer. The system has been tested in the frequency range 5.5 to 52 MHz and seems not to generate any background noise.

1. Calcium-dependent transient phosphorylation of phorphorylase b has been monitored in a rabbit muscle glycogen particle fraction. Using a phosphorus nuclear magnetic resonance assay, the changes in concentrations of small phosphate-containing metabolites associated with this event have been measured. In addition, the conformation of phosphorylase has been monitored during transient activation by observing changes in the electron spin resonance signal from added spin-labelled phosphorylase. 2. The transient activation was associated with a loss of glucose-6-phosphate from phosphorylase b; newly formed phosphorylase a binds the nucleotides ADP, AMP, or IMP. Because of the fast interconversion of these nucleotides the species bound to phosphorylase a change throughout the process. 3. Lowering the [Mg2+] : [Ca2+] ratio during transient activation causes accumulation of ADP. Electron spin resonance data from spin-labelled phosphorylase shows that, under these conditions, ADP binding to phosphorylase a is potentiated. 4. Calcium-dependent activation in the glycogen particle fraction is compared to the activation of phosphorylase in vivo.

1. The 129 MHz 31P-NMR spectrum of Acholeplasma laidlawii membranes is very similar to the spectrum of the derived liposomes and is a typical "solid state" spectrum in which the major contribution to the linewidth is made by the chemical shift anisotropy. From the value of the chemical shift anisotropy an order parameter of 0.15 is estimated for the lipid phosphates in both membranes. 2. The 31P-NMR spectrum of the A. laidlawii membrane is insensitive to pronase digestion of 4-60% of the membrane proteins and subsequent cytochrome C binding. These results indicate that either no strong lipid polar headgroup-protein interactions occur in the membrane or that the lipid-protein "complexes" in the membrane have a fast rotation (Tc shorter than 10(-6)S) along an axis perpendicular to the plane of the membrane. 3. Phospholipase A2 degrades all the phosphatidylglycerol in the membrane. The resulting membrane contains a phosphoglycolipid as the sole phosphorus-containing compound. The 31P-NMR spectrum of these membranes is identical to the spectrum of the native membranes suggesting a similar motion for the phosphate groups in both lipids. 4. Ca2+ binding to liposomes prepared from either the total polar lipids or the total phosphorus-containing lipids isolated from the A. laidlawii membrane does not affect the 21P-NMR spectrum. 5. The 31P-NMR spectrum of the membranes and derived liposomes, however, is sensitive to lipid phase transitions. When the membrane lipids are in the gel state a broadening of the 31P resonance occurs demonstrating that the polar head group motion in a biological membrane is more restricted below the lipid-phase transition temperature.

The use of 270 MHz Fourier Transform nuclear magnetic resonance (NMR) spectrometer, combined with signal processing techniques to improve resolution, enabled proton resonances from the individual aromatic residues of haemoglobin to be distinguished. In the presence of clinical concentrations of the general anaesthetic drugs halothane and methoxyflurane, specific changes in the NMR spectrum can be distinguished which probably reflect local changes of conformation. When higher concentrations of anaesthetic are used, extensive changes in the NMR spectrum occur which are consistent with non-specific binding of the anaesthetic to the hydrophobic parts of the haemoglobin molecule.

FEBS LettersVolume 57, Issue 2 p. 213-218 Full-length articleFree Access Application of 31P NMR to model and biological membrane systems A.C. McLaughlin, A.C. McLaughlin Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorP.R. Cullis, P.R. Cullis Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorM.A. Hemminga, M.A. Hemminga Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorD.I. Hoult, D.I. Hoult Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorG.K. Radda, G.K. Radda Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorG.A. Ritchie, G.A. Ritchie Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorP.J. Seeley, P.J. Seeley Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorR.E. Richards, R.E. Richards Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this author A.C. McLaughlin, A.C. McLaughlin Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorP.R. Cullis, P.R. Cullis Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorM.A. Hemminga, M.A. Hemminga Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorD.I. Hoult, D.I. Hoult Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorG.K. Radda, G.K. Radda Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorG.A. Ritchie, G.A. Ritchie Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorP.J. Seeley, P.J. Seeley Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this authorR.E. Richards, R.E. Richards Biochemistry Department, Oxford University, Oxford, EnglandSearch for more papers by this author First published: September 15, 1975 https://doi.org/10.1016/0014-5793(75)80719-8Citations: 113AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 A.G. Lee, N.J.M. Birdsall, J.C. Metcalf, E.D. Korn Methods in Membrane Biology II, (1974), Plenum Press London 2 D.G. Davis, G. Inesi, Biochim. Biophys. Acta, 282, (1972), 180– 186. 3 R. Barker, J.D. Bell, G.K. Radda, R.E. Richards, Biochim. Biophys. Acta, 260, (1972), 161– 163. 4 D.M. Michaelson, A.F. Horwitz, M.P. Klein, Biochemistry, 12, (1973), 2637– 2645. 5 J.A. Berden, R.W. Barker, G.K. Radda, Biochem. Biophys. Acta, 375, (1975), 186– 208. 6 J.A. Berden, P.R. Cullis, D.I. Hoult, A.C. McLaughlin, G.K. Radda, R.E. Richards, FEBS Lett., 46, (1974), 55– 58. 7 McLaughlin, A. C., Cullis, P. R., Berden, J. A. and Richards, R. E. J., Magn. Res., in press 8 M.P. Sheetz, S.I. Chan, Biochemistry, 11, (1972), 4573– 4581. 9 M.A. Hemminga, H.J.C. Berendson, J. Magn. Res., 8, (1972), 133– 143. 10 H.G. Rose, M. Oklander, J. Lipid Research, 6, (1965), 428– 431. 11 P. Ways, D.J. Hanahan, J. Lipid Research, 5, (1964), 318– 328. 12 A. Martinosi, R.A. Halpin, Arch. Biochem. Biophys., 152, (1972), 440– 450. 13 C.L. Bashford, G.K. Radda, G.A. Ritchie, FEBS Lett., 50, (1975), 21– 24. 14 W.L. Hubble, H.M. McConnell, J. Amer. Chem. Soc., 93, (1971), 314– 326. 15 McLaughlin, A. C. and Cullis, P. R., unpublished results. 16 S. Schreier-Muccillo, D. Marsh, H. Dugas, H. Schneider, I.C.P. Smith, Chem. Phys. Lipids, 10, (1973), 11– 27. 17 H.S. Gutowsky, G.E. Pake, J. Chem. Phys., 18, (1949), 162– 170. 18 Dijkema, C. and Berendson, H. J. C. (1974), 14, 251–259. 19 S. Abrahamsson, I. Pascher, Acta Crystallogr., 21, (1966), 70– 87. 20 M.H.F. Wilkins, A.E. Blaurock, D.M. Engelman, Nature New Biology, 230, (1971), 72– 76. Citing Literature Volume57, Issue2September 15, 1975Pages 213-218 ReferencesRelatedInformation

1. Distearoyl phosphatidylcholine and the phosphonium analogue, in which the nitrogen atom is replaced by phosphorus, show similar gel-liquid crystalline transition temperatures as detected by differential scanning calorimetry. 2. The temperature-dependence of the 31P n.m.r. (nuclear-magnetic-resonance) linewidths of the phosphate resonances of sonicated vesicles of distearoyl phosphatidylcholine and the phosphonium analogue are similar. Below the phase-transition temperature the linewidths decrease as the temperature is raised. Above the phase-transition temperature the phosphate resonances are relatively temperature-independent. The phosphonium 31P n.m.r. signal exhibits the same pattern of temperature-dependence. 3. The 31P n.m.r. phosphonium resonance is sensitive to the paramagnetic shift reagent, K3Fe(CN)6. Use of K3Fe(CN)6, together with Nd(NO3)3, enabled the determination of the trans-bilayer distribution of egg-yolk phosphatidylcholine and its phosphonium analogue in co-sonicated vesicles. Both are distributed comparably across the bilayer of the vesicles. 4. The phosphonium 31P n.m.r. signal is much sharper than the corresponding phosphate resonance in both sonicated and unsonicated dispersions of the phosphatidylcholine analogue. 5. The properties of the phosphonium analogue of phosphatidylcholine are discussed in terms of its suitability as a probe of membrane structure.

The 31P NMR spectrum of sonicated dipalmitoyl lecithin vesicles consists of two chemically shifted resonances, separated by ∼0.15 ppm, which arise from phosphate groups in phospholipid molecules on the inside and the outside of the spherical bilayer vesicles. The widths of the resonances are remarkably sensitive to the crystalline-liquid crystalline phase transition, the magnetic field-strength, and the viscosity of the surrounding aqueous medium. The results are interpreted in terms of two phosphorus relaxation mechanisms: modulation of the anisotropic phosphorus chemical shift and dipolar interaction with protons on adjacent methylene groups. At high magnetic fields (7.5 T) the modulation of the phosphorus chemical shift anisotropy by the Brownian rotation of the intact spherical vesicles dominates the linewidth.

FEBS LettersVolume 55, Issue 1-2 p. 14-17 Full-length articleFree Access Pyridoxal phosphate in glycogen phosphorylase: A phosphorous NMR study S.J.W. Busby, S.J.W. Busby Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorD.G. Gadian, D.G. Gadian Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorG.K. Radda, G.K. Radda Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorR.E. Richards, R.E. Richards Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorP.J. Seeley, P.J. Seeley Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this author S.J.W. Busby, S.J.W. Busby Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorD.G. Gadian, D.G. Gadian Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorG.K. Radda, G.K. Radda Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorR.E. Richards, R.E. Richards Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this authorP.J. Seeley, P.J. Seeley Department of Biochemistry, University of Oxford, Oxford, UKSearch for more papers by this author First published: July 15, 1975 https://doi.org/10.1016/0014-5793(75)80945-8Citations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 D.J. Graves, J.H. Wang, P.D. Boyer 3rd Edn. The Enzymes VII, (1972), Academic Press New York 435– 482. 2 S. Shaltiel, J.L. Hedrick, A. Pocker, E.H. Fisher, Biochemistry, 8, (1969), 5189– 5196. 3 K. Feldman, H. Zeisel, E. Helmreich, Proc. Natl. Acad. Sci. U.S., 69, (1972), 2278– 2282. 4 S. Bresler, L. Firsov, E. Glasunov, Nature, 211, (1966), 1262– 1265. 5 M.H. Buc-Caron, F. Faure, L.C. Oudin, M. Morange, B. Vandenbunder, H. Buc, Biochimie, 56, (1974), 477– 489. 6 K.O. Honikel, N.B. Madsen, Can. J. Biochem., 51, (1973), 344– 356. 7 D.J. Brooks, S.J.W. Busby, G.K. Radda, Eur. J. Biochem., 48, (1974), 571– 578. 8 J.R. Griffiths, N.C. Price, G.K. Radda, Biochim. Biophys. Acta, 358, (1974), 275– 280. 9 D.I. Hoult, R.E. Richards, Proc. Roy. Soc. Lond. A., (1975), in press Citing Literature Volume55, Issue1-2July 15, 1975Pages 14-17 ReferencesRelatedInformation

An analysis is given of the factors which influence the performance of a Fourier transform n.m.r. spectrometer including field homogeneity, probe design, transient circuit behaviour, Johnson noise, non linear analysis, phase sensitive detection in quadrature, and signal processing. The building of a spectrometer based upon the analysis of these factors is described, as is the use of a cyclically ordered phase sequence (CYCLOPS) which renders the use of quadrature Fourier transformation easy. Theoretical deductions are experimentally verified, and the performance of the instrument is demonstrated with spectra obtained from caesium and phosphorus resonances.

An attempt is made to clarify the relation between the empirical logarithmic law and the theory developed by Halliday, Richards & Sharp (1969) to describe and account for the concentration dependence of the nuclear resonance frequency of the caesium ion in solution. It is shown that the range of validity of the empirical law is expected to diminish as the dielectric constant of the solvent falls, and nonlinear regression to a simplified form of the full theoretical equation is proposed as a preferable method of obtaining infinite dilution resonance frequencies. New experimental data are presented to test the predictions of the theory in respect to changes in (i) dielectric constant, (ii) temperature, (iii) ionic strength, and we conclude that the results provide substantial confirmation of the theory.

1.1. Phosphoglucomutase (α-d-glucose-1,6-bisphosphate: α-d-glucose-1-phosphate phosphotransferase, EC 2.7.5.1) has been assayed by monitoring the proton and phosphorus nuclear magnetic resonances of glucose 1-phosphate and glucose 6-phosphate as a function of time.2.2. The activity of phosphoglucomutase in 2H2O is 70% of that in H2O.3.3. Both anomers of glucose 6-phosphate bind to phosphoglucomutase, although the enzyme is specific to the α-anomer.4.4. The Mn2+-binding site on phosphoglucomutase is 5.8 Å from the phosphorus of bound glucose 6-phosphate.5.5. The protons of bound glucose 6-phosphate are about 7–10 Å from the Mn2+-binding site.

FEBS LettersVolume 46, Issue 1-2 p. 55-58 Full-length articleFree Access Frequency dependence of 31P NMR linewidths in sonicated phospholipid vesicles: Effects of chemical shift anisotropy J.A. Berden, J.A. Berden Department of Biochemistry, Oxford University, Oxford, UK Supported by the Netherlands Organisation for the Advancement of Scientific Research (Z.W.O.). Present address: Laboratory of Biochemistry, University of Amsterdam, B. C. P. Jansen Institute, Amsterdam. Search for more papers by this authorP.R. Cullis, P.R. Cullis Department of Biochemistry, Oxford University, Oxford, UK Medical Research Council (Canada) Post-Doctoral Fellow 1973–74. Search for more papers by this authorD.I. Hoult, D.I. Hoult Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this authorA.C. McLaughlin, Corresponding Author A.C. McLaughlin Department of Biochemistry, Oxford University, Oxford, UKTo whom correspondence should be addressed.Search for more papers by this authorG.K. Radda, G.K. Radda Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this authorR.E. Richards, R.E. Richards Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this author J.A. Berden, J.A. Berden Department of Biochemistry, Oxford University, Oxford, UK Supported by the Netherlands Organisation for the Advancement of Scientific Research (Z.W.O.). Present address: Laboratory of Biochemistry, University of Amsterdam, B. C. P. Jansen Institute, Amsterdam. Search for more papers by this authorP.R. Cullis, P.R. Cullis Department of Biochemistry, Oxford University, Oxford, UK Medical Research Council (Canada) Post-Doctoral Fellow 1973–74. Search for more papers by this authorD.I. Hoult, D.I. Hoult Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this authorA.C. McLaughlin, Corresponding Author A.C. McLaughlin Department of Biochemistry, Oxford University, Oxford, UKTo whom correspondence should be addressed.Search for more papers by this authorG.K. Radda, G.K. Radda Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this authorR.E. Richards, R.E. Richards Department of Biochemistry, Oxford University, Oxford, UKSearch for more papers by this author First published: September 15, 1974 https://doi.org/10.1016/0014-5793(74)80333-9Citations: 73 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References 1 R.W. Barker, J.D. Bell, G.K. Radda, R.E. Richards, Biochim. Biophys. Acta, 260, (1972), 161– 163. 2 D.G. Davis, Biochem. Biophys. Res. Commun., 49, (1972), 1492– 1497. 3 D.G. Davis, G. Inesi, Biochim. Biophys. Acta, 282, (1972), 180– 186. 4 M.P. Sheetz, S.I. Chan, Biochemistry, 11, (1972), 4573– 4581. 5 D.M. Michaelson, A.F. Hornitz, M.P. Klein, Biochemistry, 12, (1973), 2637– 2645. 6 T.O. Henderson, T. Gloner, T.C. Myers, Biochemistry, 13, (1974), 623– 628. 7 D. Hoult, D. Phil. Thesis, (1973), Oxford 8 P.J. Devaux, H.M. McConnell, J. Amer. Chem. Soc., 94, (1972), 4475– 4481. 9 T.C. Farrar, E.D. Becker, Pulse and Fourier Transform NMR (1971), Academic Press New York 59– Citing Literature Volume46, Issue1-2September 15, 1974Pages 55-58 ReferencesRelatedInformation

14 N Nuclear resonances have been observed in a 7·5 T magnetic resonance spectrometer. 55 Compounds of biological interest were studied in aqueous solutions of concentration ca. 200 mM, and the chemical shifts and relaxation times of the 14N resonances recorded. The chemical shifts are discussed in terms of structures, and the relaxation times in terms of nuclear quadrupole coupling constants and molecular correlation times.