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Lanthanides as probes for calcium in biological systems

Published online by Cambridge University Press:  17 March 2009

Bruce Martin  and
Frederick S. Richardson
Bruce Martin
Affiliation:
Chemistry Department, University of Virginia, Charlottesville, VA 22901
Frederick S. Richardson
Affiliation:
Chemistry Department, University of Virginia, Charlottesville, VA 22901
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Calcium ion plays an essential role in many biological processes. The environment about Ca2+ may be probed by substitution of tripositive lanthanide ions, Ln3+. Ca2+ proteins fall into two broad classes: those that are inhibited by Ln3+ substitution and those that are not. It is suggested that although Ca2+ undertakes a primarily structural role in the Ln3+ non-inhibited proteins, Ca2+ may be near the active site or participate in the mechanism of action of Ln3+ inhibited proteins. Ca2+ and Ln3+ radii are similar; most Ln3+ are slightly larger than Ca2+ in complexes of the same coordination number, and substitution of Ln3+ for Ca2+ is accommodated by a slight decrease in bond distance or by an increase in coordination number. Luminescence from Tb3+ has been demonstrated to be a sensitive environmental probe of Ca2+ binding sites in proteins.

Type
Research Article
Information
Quarterly Reviews of Biophysics , Volume 12 , Issue 2 , May 1979 , pp. 181 - 209
Copyright
Copyright © Cambridge University Press 1979

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References

IX. REFERENCES

Abbott, F., Darnall, D. W. & Birnbaum, E. R. (1975 a). The location of the lanthanide ion binding site on bovine trypsin. Biochem. biophys. Res. Commun. 65, 241–247.CrossRefGoogle ScholarPubMed
Abbott, F., Gomez, J. E., Birnabaum, E. R. & Darnall, D. W. (1975 b). The location of the lanthanide ion binding site on bovine trypsin. Biochemistry, N.Y. 14, 4935–4943.CrossRefGoogle Scholar
Bajaj, S. P., Butkowski, R. J. & Mann, K. G. (1975). Prothrombin fragments (Ca2+ binding and activation kinetics). J. biol. Chem. 250, 2150–2156.CrossRefGoogle ScholarPubMed
Batra, S. (1973). The effects of zinc and lanthanum on calcium uptake by mitochondria and fragmented sarcoplasmic reticulum of frog skeletal muscle. J. cell comp. Physiol. 82, 245–256.CrossRefGoogle ScholarPubMed
Birnbaum, E. R., Gomez, J. E. & Darnall, D. W. (1970). Rare earth metal ions as probes of electrostatic binding sites in proteins. J. Am. chem. Soc. 92, 5287–5288.CrossRefGoogle ScholarPubMed
Birnbaum, E. R., Abbott, F., Gomez, J. E. & Darnall, D. W. (1977). The calcium ion binding site in bovine chymotrypsin A. Archs Biochem. Biophys. 179, 469–476.CrossRefGoogle ScholarPubMed
Boucek, M. M. & Snyderman, R. (1976). The calcium influx requirement for human neutrophile chemotaxis: inhibition by lanthanum chloride. Science, N. Y. 193, 905–907.CrossRefGoogle ScholarPubMed
Brittain, H. G. & Richardson, F. S. (1976). pH dependence of circularly polarized emission and total emission from europium(III)/L-malic acid and europium(III)/L-malic acid/terbium(III) complexes in H2O and D2O solutions. Inorg. Chem. 15, 1507–1511.CrossRefGoogle Scholar
Brittain, H. G. & Richardson, F. S. (1977). Circularly polarized emission studies on Tb3+:and Eu3+:complexes with potentially terdentate amino acids in aqueous solution. Bioinorg. Chem. 7, 233–243.CrossRefGoogle Scholar
Brittain, H. G., Richardson, F. S. & Martin, R. B. (1976 a). Terbium(III) emission as a probe of calcium(II) binding sites in proteins. J. Am. chem. Soc. 98, 8255–8260.CrossRefGoogle ScholarPubMed
Brittain, H. G., Richardson, F. S., Martin, R. B., Burtnick, L. D. & Kay, C. M. (1976 b). Circularly polarized emission of terbium(III) substituted bovine cardiac troponin-C. Biochem. biophys. Res. Commun. 68, 1013–1019.CrossRefGoogle ScholarPubMed
Burton, J. & Godfraind, T. (1974). Sodium-calcium sites in smooth muscle and their accessibility to lanthanum. J. Physiol., Lond. 241, 287–298.CrossRefGoogle ScholarPubMed
Butchard, C. G., Dwek, R. A., Kent, P. W., Williams, R. J. P. & Xavier, A. V. (1972). A structural study by 19F-nuclear-magnetic resonance of the binding of sugars to lysozyme. Eur. J. Biochem. 27, 548–553.CrossRefGoogle Scholar
Butler, L. G. & Sperow, J. W. (1977). Multiple roles of metal ions in the reaction catalyzed by yeast inorganic pyrophosphatase. Bioinorg. Chem. 7, 141–150.CrossRefGoogle ScholarPubMed
Campbell, I. D., Dodson, C. M. & Williams, R. J. P. (1975). Nuclear magnetic resonance studies on the structure of lysozyme in solution. Proc. R. Soc. A 345, 41–59.Google Scholar
Chelvalier, J. & Butow, R. A. (1971). Calcium binding to the sarcoplasmic reticulum of rabbit skeletal muscle. Biochemistry, N.Y. 10, 2733–2737.Google Scholar
Coffee, C. J. & Bradshaw, R. A. (1973). Carp muscle calcium-binding protein. Part I. J. biol. Chem. 248, 3305–3312.CrossRefGoogle Scholar
Collins, J. H. (1974). Homology of myosin light chains, troponin-C and parvalbumin deduced from comparison of their amino acid sequences. Biochem. biophys. Res. Commun. 58, 301–308.CrossRefGoogle ScholarPubMed
Cooperman, B. S. & Chiu, N. Y. (1973). Yeast inorganic pyrophosphatase. II. Magnetic resonance and steady state kinetic studies of metal binding. Biochemistry, N.Y. 12, 1670–1676.CrossRefGoogle Scholar
Cottam, G. L., Valentine, K. M., Thompson, B. C. & Sherry, A. D. (1974). Magnetic resonance studies of the formation of the ternary phospho-enolpyruvate–gadolinum muscle pyruvate kinase complex. Biochemistry, N.Y. 13, 3532–3537.CrossRefGoogle ScholarPubMed
Dahlquist, F. W., Long, J. W. & Bigbee, W. L. (1976). Role of calcium in the thermal stability of thermolysin. Biochemistry, N.Y. 15, 1103–1111.CrossRefGoogle ScholarPubMed
Darnall, D. W., Abbott, F., Gomez, J. E. & Birnbaum, E. R. (1976). Fluorescence energy-transfer measurements between the calcium binding site and the specificity pocket of bovine trypsin using lanthanide probes. Biochemistry, N.Y. 15, 5017–5023.CrossRefGoogle ScholarPubMed
Darnall, D. W. & Birnbaum, E. R. (1973). Lanthanide ions activate α-amylase. Biochemistry, N.Y. 12, 3489–3491.CrossRefGoogle ScholarPubMed
Darnall, D. W. & Birnbaum, E. R. (1976). The metal ion acceleration of the activation of trypsinogen to trypsin. In Metal Ions in Biological Systems, vol. 6 (ed. Sigel, H.), chapter 4, pp. 251–290. New York: Marcel Dekker.Google Scholar
Dimicoli, J. L. & Bieth, J. (1977). Location of the calcium binding site in porcine pancreatic elastase using a lanthanide ion probe. Biochemistry, N.Y. 16, 5532–5537.CrossRefGoogle ScholarPubMed
Donato, H. Jr & Martin, R. B. (1974). Conformations of carp muscle calcium binding parvalbumin. Biochemistry, N.Y. 13, 4575–4579.CrossRefGoogle ScholarPubMed
Dwek, R. A., Knott, J. C. A., Marsh, D., McLaughlin, A. C., Press, E. M., Price, N. C. & White, A. I. (1975). Structural studies on the combining site of the myeloma protein MOPC 315. Eur. J. Biochem. 53, 25–39.CrossRefGoogle Scholar
Entman, M. L., Hansen, J. L. & Cook, J. W. Jr, (1969). Calcium metabolism in cardiac microsomes incubated with lanthanum ion. Biochem. biophys. Res. Commun. 35, 258–264.CrossRefGoogle ScholarPubMed
Epstein, M., Levitzki, A. & Reuben, J.(1974). Binding of lanthanides and of divalent metal ions to porcine trypsin. Biochemistry, N.Y. 13, 1777–1782.CrossRefGoogle ScholarPubMed
Epstein, M., Reuben, J. & Levitzki, A. (1977). Calcium binding site of trypsin as probed by lanthanides. Biochemistry, N.Y. 16, 2449–2457.CrossRefGoogle ScholarPubMed
Formoso, C. (1973). Fluorescence of nucleic acid-terbium(III) complexes. Biochem. biophys. Res. Commun. 53, 1084–1082.CrossRefGoogle Scholar
Forster, T. (1959). Transfer mechanism of electronic excitation. Disc. Farad. Soc. 27, 7–17.CrossRefGoogle Scholar
Furie, B. C. & Fuire, B. (1975). Interaction of lanthanide ions with bovine factor X and their use in the affinity chromatography of the venom coagulant protein of Vipera reisselli. J. biol. Chem. 250, 601–608.CrossRefGoogle Scholar
Furie, B., Eastlake, A., Schechter, A. N. & Anfinsen, C. B. (1973). The interaction of the lanthanide ions with staphylococcal nuclease. J. biol. Chem. 248, 5821–5825.CrossRefGoogle ScholarPubMed
Furie, B., Griffen, J. H., Feldman, R. J., Sokoloski, E. A. & Schechter, A. N. (1974). The active site of staphylococcal nuclease: paramagnetic relaxation of bound nucleotide inhibitor nuclei by lanthanide ions. Proc. natn. Acad. Sci. U.S.A. 71, 2833–2837.CrossRefGoogle ScholarPubMed
Furie, B. C., Mann, K. G. & Furie, B. (1976). Substitution of lanthanide ions for calcium ions in the activation of bovine prothrombin by activated factor X. J. biol. Chem. 251, 3235–3241.CrossRefGoogle ScholarPubMed
Gafni, A. & Steinberg, I. Z. (1974). Optical activity of terbium ions bound to transferrin and conalbumin studied by circular polarization of luminescence. Biochemistry, N. Y. 13, 800–803.CrossRefGoogle ScholarPubMed
Gomez, J. E., Birnbaum, E. R. & Darnali, D. W. (1974). The metal ion acceleration of the conversion of trypsinogen to trypsin. Lanthanide ions as calcium ion substitutes. Biochemistry, N.Y. 13, 3745–3750.CrossRefGoogle ScholarPubMed
Hellman, B., Sehlen, J. & Taljedal, I. B. (1976 a). Calcium and secretion:distinction between a pools of glucose-sensitive calcium in pancreaticislets. Science, N.Y. 194, 1421–1423.CrossRefGoogle Scholar
Hellman, B., Sehlen, J. & Teljedal, I. B. (1976 b). Effects of glucose on 43Ca2+ uptake by pancreatic islets as studied with the lanthanum method. J. Physiol., Lond. 254, 639–656.CrossRefGoogle Scholar
Henrickson, R. A. & Jackson, C. M. (1975). Cooperative calcium binding by the phospholipid binding region of bovine prothrombin: a requirement for intact disulfide bridges. Archs: Biochem. Biophys. 170, 149–159.Google Scholar
Hermsmeyer, K. & Sperelakis, N. (1970). Decrease in K: conductance and depolarization of frog cardiac muscle produced by Ba++. J. Physiol. 219, 1108–1114.Google Scholar
Horrocks, W. D. Jr, Schmidt, G. F., Sudnick, D. R., Kittrell, C. & Bernhein, R. A. (1977). Laser-induced lanthanide ion luminescence lifetime measurements by direct excitation of metal ion levels. A new class of structural probe for calcium-binding proteins and nucleic acids. J. Am. chem. Soc. 99, 2378–2380.CrossRefGoogle Scholar
Hutton, W. C., Yeagle, P. L. & Martin, R. B. (1977). The interaction of lanthanide and calcium salts with phospholipid bilayer vesicles: the validity of the nuclear magnetic resonance method for determination of vesicle bilayer phospholipid surface ratios. Chem. Phys. Lipids. 19, 255–265.CrossRefGoogle ScholarPubMed
Izutsu, K. T., Felton, S. P., Siegal, I. A., Yoda, W. T. & Chen, A. C. N. (1972). Aequorin: its ionic specificity. Biochem. biophys. Res. Commun. 49, 1034–1039.CrossRefGoogle ScholarPubMed
Jones, R., Dwek, R. A. & Forsen, S. (1974). The mechanism of water- proten relaxation in enzyme paramagnetic-ion complexes. Eur. J. Biochem. 27, 548–553.Google Scholar
Jones, C. R. & Kearns, D. R.(1974). Paramagnetic rare earth ion probes of transfer ribonucleic acid structure. J. Am. chem. Soc. 96, 3651–3653.CrossRefGoogle ScholarPubMed
Kass, R. S. & Tsien, R. W. (1975). Multiple effects of calcium antagonists on plateau currents in cardiac Purkinje fibers. J. gen. Physiol. 66, 169–192.CrossRefGoogle ScholarPubMed
Katzung, B. G., Reuter, H. & Porzig, H.(1973). Lanthanum inhibits Ca inward current but not Na-Ca exchange in cardiac muscle. Experientia 29, 1073–1075.CrossRefGoogle Scholar
Kayne, M. S. & Cohn, M. (1972). Cation requirements of isoleucyl-tRNA synthetase from Escherichia coli. Biochem biophys. Res. Commun. 46, 1285–1291.CrossRefGoogle ScholarPubMed
Kayne, M. S. & Cohn, M. (1974). Enhancement of Tb(III) and Eu(III) fluorescence in complexes with Escherichia coli tRNA. Biochemistry, N.Y. 13, 4159–4165.CrossRefGoogle ScholarPubMed
Krasnow, N. (1972). Effects of lanthanum and gadolinium ions on cardiac sarcoplasmic reticulum. Biochim. biophys. Acta 282, 187–194.CrossRefGoogle ScholarPubMed
Krasnow, N. (1977). Lanthanide binding to cardiac and skeletal muscle microsomes. Archs Biochem. Biophys. 181, 322–330.CrossRefGoogle ScholarPubMed
Kretsinger, R. H. & Nelson, D. J. (1976). Calcium in biological systems. Coord. Chem. Revs. 18, 29–124.CrossRefGoogle Scholar
Kretsinger, R. H. & Nockolds, C. E. (1973). Carp muscle calcium-binding protein. Part II. J. biol. Chem. 248, 3313–3326.CrossRefGoogle Scholar
Kurachi, K., Sieker, L. C. & Jensen, L. H. (1975). Metal binding in triclinic lysozyme. J. biol. Chem. 250, 7663–7667.CrossRefGoogle ScholarPubMed
Lambert, D. H. & Parsons, R. L. (1970). Influence of polyvalent cations on the activation of muscle end plate receptors. J. gen. Physiol. 56, 309–321.CrossRefGoogle ScholarPubMed
Langer, G. A. & Frank, J. S. (1972). Lanthanum in heart cell culture (effect on calcium exchange correlated with its localization). J. Cell Biol. 54, 441–455.CrossRefGoogle ScholarPubMed
Lehninger, A. L. & Carafoli, E. (1971). The interaction of La3+ with mitochondria in relation to respiration-coupled Ca3+ transport. Arch Biochem. Biophys. 143, 506–515.CrossRefGoogle Scholar
Longworth, J. W. (1971). Luminescence of polypeptides and proteins. In Excited States of Protein and Nucleic Acids (ed. Steiner, R. F. and Weinryb, I.), pp. 319–484. New York: Plenum.CrossRefGoogle Scholar
Luk, C. K. (1971). Study of the nature of the metal-binding site and estimate of the distance between the metal binding sites in transferrin using trivalent lanthanide ions as fluorescent probes. Biochemistry, N.Y. 10, 2838–2843.CrossRefGoogle Scholar
Luk, C. K. & Richardson, F. S. (1975). Circularly polarized luminescence and energy transfer studies on carboxylic acid complexes of europium(III) and terbium(III) in solution. J. Am. chem. Soc. 97, 6666–6675.CrossRefGoogle Scholar
Matthews, B. W. & Weaver, L. H. (1974). Binding of thermolysin. Biochemistry, N.Y. 13, 1719–1725.CrossRefGoogle ScholarPubMed
Meissner, G. (1973). ATP and Ca2+ binding by the Ca2+ pump protein of sarcoplasmic reticulum. Biochim. biophys. Acta 298, 906–926.CrossRefGoogle ScholarPubMed
Mela, L. (1968). Interaction of La3+ and local anaesthetic drugs with mitochondrial Ca++ and Mn++ uptake. Archs Biochem. Biophys. 123, 286–293.CrossRefGoogle ScholarPubMed
Mela, L. (1969). Inhibition and activation of calcium transport in mitochondria. Effects of lanthanides and local anesthetic drugs. Biochemistry, N.Y. 8, 2481–2486.CrossRefGoogle ScholarPubMed
Mela, L. & Chance, B. (1969). Calcium cariier and the ‘high affinity calcium binding site’ in mitochondria. Biochem. biophys. Res. Commun. 35, 556–559.CrossRefGoogle ScholarPubMed
Mikkelsen, R. B. & Wallach, D. F. H. (1974 a). High affinity calcium binding sites on erythrocyte membrane proteins. Biochim. biophys. Acta. 363, 211–218.CrossRefGoogle ScholarPubMed
Mikkelsen, R. B. & Wallach, D. F. H. (1974 b). Lanthanides as calcium probes in biomembranes. J. Cell Biol. 63, 225a.Google Scholar
Mikkelsen, K. B. & Wallach, D. F. H. (1976). Binding of fluorescent lanthanides to rat liver mitochondrial membranes and calcium ion- binding proteins. Biochim. biophys. Acta 433, 674–683.CrossRefGoogle ScholarPubMed
Miller, T. L., Nelson, D. J., Brittain, H. G., Richardson, F. S., Martin, R. B. & Kay, C. M. (1975). Calcium binding sites of iabbit troponin and carp parvalbumin. FEBS Lett. 58, 262–264.CrossRefGoogle ScholarPubMed
Mines, G. R. (1910). The action of beryllium, lanthanum, yttrium, and cerium on the frog's heart. J. Physiol., Lond. 40, 327–346.CrossRefGoogle ScholarPubMed
Moews, P. C. & Kretsinger, R. H. (1975 a). Refinement of the structure of carp muscle calcium-binding. Parvalbumin by model building and difference fourier analysis. J. molec. Biol. 91, 201–228.CrossRefGoogle ScholarPubMed
Mowes, P. C. & Kretsinger, R. H. (1975 b). Terbium replacement of calcium in carp muscle calcium-binding parvalbumin: an X-ray crystallographic study. J. molec. Biol. 91, 229–232.CrossRefGoogle Scholar
Moyle, J. & Mitchell, P. (1977 a). Electrical charge stoichiometry of calcium translocation in rat liver mitochondria. FEBS Lett. 73, 131–135.CrossRefGoogle Scholar
Moyle, J. & Mitchell, P. (1977 b). The lanthanide-sensitive calcium phosphate porter of rat liver mitochondria. FEBS Lett. 77, 136–140.CrossRefGoogle ScholarPubMed
Nagahashi, G., Thompson, W. W. & Leonard, R. T. (1974). The casparian strip as a barrier to the movement of lanthanum in corn roots. Science, N.Y. 183, 670–671.CrossRefGoogle Scholar
Nelson, D. J., Miller, T. L. & Martin, R. B. (1977). Non-cooperative Ca(II) removal and terbium(III) substitution in carp muscle calcium binding parvalbumin. Bioinorg Chem. 7, 325–334.CrossRefGoogle ScholarPubMed
Nieboer, E. (1975). The lanthanide ions as structural probes in biological and model systems. Struct. and Bond. 22, 1–47.CrossRefGoogle Scholar
Peacocke, A. R. & Williams, P. A. (1966). Binding of calcium, yttrium and thorium to a glycoprotein from bovine cortical bone. Nature, Lond. 211, 1140–1141.CrossRefGoogle ScholarPubMed
Prados, R., Stradtherr, L. G., Donato, H. Jr, & Martin, R. B. (1974). Lanthanide complexes of amino acids. J. inorg. nucl. Chem. 36, 689–693.CrossRefGoogle Scholar
Reed, K. C. & Bygrave, F. L. (1974 a). Accumulation of lanthanum by rat liver mitochondria. Biochem. J. 138, 239–252.CrossRefGoogle ScholarPubMed
Reed, K. C. & Bugrave, F. L. (1974 b). The inhibition of mitochondrial calcium transport by lanthanides and ruthenium red. Biochem. J. 140, 143–155.CrossRefGoogle ScholarPubMed
Reuben, J. (1971 a). Gadolinium (III) as a paramagnetic probe for proton relaxation studies of biological macromolecules binding to bovine serum albumin. Biochemistry, N.Y. 10, 2834–2838.CrossRefGoogle Scholar
Reuben, J. (1971 b). Electron spin relaxation in aqueous solutions of gadolinium (III) Aquo, cacodylate, and bovine serum albumin complexes. J. Phys. Chem. 75, 3164–3167.CrossRefGoogle Scholar
Richardson, F. S. & Riehl, J. P. (1977). Circularly polarized luminescence spectroscopy. Chem. Rev. 77, 773–854.CrossRefGoogle Scholar
Ringer, D. P., Burchett, S. & Kizer, D. E. (1978). Use of terbium(III) fluorescence enhancement to selectively monitor DNA and RNA guanine residues and their alteration by chemical modification. Biochemistry, N.Y. 17, 4818–4825.CrossRefGoogle ScholarPubMed
Rubsamen, H., Hess, G. P., Eldefrawi, A. T. & Eldefrawi, M. E. (1976 a). Interaction between calcium and ligand-binding sites of the purified acetylcholine receptor studied by use of a fluorescent lanthanide. Biochem. biophys. Res. Commun. 68, 56–63.CrossRefGoogle ScholarPubMed
Rubsamen, H., Montgomery, M., Hess, G. P., Eldefrawi, A. T. & Eldefrawi, M. E. (1976 b). Identification of a calcium-binding subunit of the acetyicholine receptor. Biochem. biophys. Res. Commun. 70, 1020–1027.CrossRefGoogle Scholar
Sanborn, W. G. & Langer, G. A. (1970). Specific uncoupling of excitation and contraction in mammalian cardiac tissue by lanthanum. J. gen. Physiol. 56, 191–217.CrossRefGoogle ScholarPubMed
Scarpa, A. & Azzone, G. T. (1970). The mechanism of ion translocation in mitochondria. Eur. J. Biochem. 12, 328–335.CrossRefGoogle ScholarPubMed
Schatzmann, H. J. & Tschabold, M. (1971). The lanthanides Ho3+ and Pr3+ as inhibitors of calcium transport in human red cells. Experientia 27, 59–61.CrossRefGoogle ScholarPubMed
Shannon, R. D. (1976). Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta crystallogr. A32, 751–767.CrossRefGoogle Scholar
Sherry, A. D., Newman, A. D. & Gutz, C. G. (1975). The activation of concanavalin A by lanthanide ions. Biochemistry, N.Y. 14, 2191–2196.CrossRefGoogle ScholarPubMed
Shimomura, O. & Johnson, F. H. (1973). Further data on the specificity of aequorin luminescence to calcium. Biochem. biophys. Res. Commun. 53, 490–494.CrossRefGoogle ScholarPubMed
Siegel, F. L. (1973). Biological functions of calcium. Struct. Bond. 17, 222–224.Google Scholar
Smolka, G. E., Birnbaum, E. R. & Darnall, D. W. (1971). Rare earth metal ions as substitutes for the calcium ion in Bacillus subtilis α-amylase. Biochemistry, N.Y. 10, 4556–4561.CrossRefGoogle Scholar
Sperelakis, N., Schneider, M. F. & Harris, E. J. (1967). Decreased K+ conductance produced by Ba++ in frog sartorius fibers. J. gen. Physiol. 50, 1563–1583.CrossRefGoogle Scholar
Sperelakis, N., Valle, R., Orozco, C., Martinez-Palomo, A. & Rubio, R. (1970). Electromechanical uncoupling of frog skeletal muscle by possible change in sarcoplasmic reticulum content. Am. J. Physiol. 225, 793–800.CrossRefGoogle Scholar
‘STABILITY CONSTANTS’ (1964, 1971). Special publications nos. 17 and 25, The Chemical Society, London.Google Scholar
Stein, G. & Wurzberg, E. (1975). Energy gap law in the solvent isotope effect on radiationless transitions of rare earth ions. J. chem. Phys. 62, 208–213.CrossRefGoogle Scholar
Stenflo, J. & Ganrot, P. O. (1973). Binding of Ca2+ to normal and dicoumarol-induced prothrombin. Biochem. biophys. Res. Commun. 50, 98–104.CrossRefGoogle Scholar
Takata, M., Pickard, W. F., Lettvin, J. W. & Moore, J. W. (1966). Ionic conductance changes in lobster axon membrane when lanthanum is substituted for calcium. J. gen. Physiol. 50, 461–471.CrossRefGoogle ScholarPubMed
Valentink, K. M. & Cottam, G. L. (1973). Gadolinium as a probe of the alkaline earth and ATP-metal binding sites in pyruvate kinase. Arch Biochem. Biophys. 158, 346–354.CrossRefGoogle Scholar
van, Breeman C. (1969). Blockade of membrane calcium fluxes by lanthanum in relation to vascular smooth muscle contractility. Archs in Physiol. Biochim. 77, 710–716.Google Scholar
van, Breeman C. & de, Weer P. (1970). Lanthanum inhibition of 45Ca efflux from the squid giant axon. Nature, Lond. 226, 760–761.Google Scholar
van, Breeman C., Farinas, B. R., Gerba, P. & McNaughton, E. D. (1972). Excitation-contraction coupling in rabbit aorta studied by the lanthanum method for measuring cellular calcium influx. Circulation Res. 30, 44–54.Google Scholar
van, Breeman D. & van, Breeman C. (1969). Calcium exchange diffusion in porous phospholipid ion-exchange membrane. Nature, Lond. 223, 898–900.Google Scholar
van, Eerd J. P. & Takahashi, K. (1975). The amino acid sequence of bovine cardiac troponin-C. Comparison with rabbit skeletal troponin-C. Biochem. biophys. Res. Commun. 64, 122–127.Google Scholar
Voordouw, G., Milo, C. & Roche, R. S. (1976). Role of bound calcium ions in thermostable, proteolytic enzymes. Separation of intrinsic and calcium ion contributions to the kinetic thermal stability. Biochemistry, N.Y. 15, 3716–3724.CrossRefGoogle Scholar
Welder, F. C. & D'Aurora, V. (1974). Spectroscopic probes of Escherichia coil glutamine synthetase (rare earth ions by difference absorption). Biochim. biophys. Acta 371, 432–441.Google Scholar
Weiss, G. (1970). On site of action of lanthanum in frog sartorius muscle. J. Pharmac. exp. Ther. 174, 517–526.Google ScholarPubMed
Weiss, G. B. & Goodman, F. R. (1969). Effects of lanthanum on contraction, calcium distribution and Ca45 movements in intestinal smooth muscle. J. Pharmac. exp. Ther. 169, 46–55.Google ScholarPubMed
Wolfson, J. M. & Kearns, D. R. (1974). Europium as a fluorescent probe of metal binding sites on transfer ribonucleic acid. I. Binding to Escherichia coli formylmethionine transfer ribonucleic acid. J. Am. chem. Soc. 96, 3653–3654.CrossRefGoogle ScholarPubMed
Wolfson, J. M. & Kearns, D. R. (1975). Europium as a fluorescent probe of transfer RNA structure. Biochemistry, N.Y. 14, 1436–1444.CrossRefGoogle ScholarPubMed