Archives of Toxicology

, Volume 54, Issue 1, pp 61–70 | Cite as

Lead and other metals can substitute for Ca2+ in calmodulin

  • E. Habermann
  • K. Crowell
  • P. Janicki
Original Investigations


We have studied the interaction between some heavy metal ions, as compared with earth alkali ions, and calmodulin, a tissue protein which binds Ca2+ and mediates some of its effects.
  1. 1.

    Calmodulin dependent phosphodiesterase was activated with Pb2+, Ca2+, Sr2+, Ba2+, and Cd2+ (EC50 about 0.8 μM). The maximal activation achieved decreases in the order given. Hg2+ Sn2+, Fe2+, Cu2+, Ni2+, Bi3+, and Sb3+ up to 20 μM did not activate.

  2. 2.

    Pb2+ can replace Ca2+ with respect to the calmodulin-dependent phosphorylation of brain membranes. With high Pb2+ concentrations, phosphorylation was inhibited.

  3. 3.

    Calmodulin binding to brain membranes was enhanced with concentrations below 10−4 M in the following order: Pb2+ ≧Ca2+ ∼ Sr2+ > Cd2+ > Mn2+ > Ba2+. In contrast Mg2+, Hg2+, Sn2+, Fe2+, Ni2+, Co2+, and Cu2+ triggered, if at all, a non-saturable binding of calmodulin.

  4. 4.

    In the flow-dialysis, other ions competed with 45Ca2+ binding to calmodulin in the following order: Pb2+ ∼ Ca2+ > Mn2+, Ba2+, Cd2+, Sr2+.


Thus among the ions investigated Pb2+ is a fully potent substitute for Ca2+ in every calmodulin-dependent reaction investigated. Cd2+ is always much less potent. The earth alkali ions Sr2+ and Ba2+ take an intermediate position. It remains to be shown whether calmodulin is merely a storage site for Pb2+, or whether the resulting functional changes play a role in Pb2+ poisoning.

Key words

Calmodulin Ca2+ Pb2+ Phosphodiesterase Phosphorylation Brain 



That concentration of an agent which leads to 50% of the maximal effect


Ethylene-glycol-bis-(2-amino ethyl ether)-N,N′-tetra acetic acid


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bartfai T (1979) Preparation of metal-chelate complex and the design of steady-state kinetic experiments involving metal nucleotide complexes. Adv Cyclic Nucleotide Res 10: 219–221PubMedGoogle Scholar
  2. Butcher RW, Sutherland EW (1962) Adenosine 3′,5′phosphate in biological materials. I. Purification and properties of cyclic 3′,5′-nucleotide phosphodiesterase and use of this enzyme to characterize adenosine 3′,5′-phosphate in human urine. J Biol Chem 237: 1244–1250PubMedGoogle Scholar
  3. Chafouleas JG, Dedman JR, Munjaal RP, Means AR (1979) Calmodulin. Development and application of a sensitive radioimmunoassay. J Biol Chem 254: 10262–10267PubMedGoogle Scholar
  4. Charbonneau H, Cormier MJ (1979) Purification of plant calmodulin by fluphenazine-sepharose affinity chromatography. Biochem Biophys Res Commun 90: 1039–1047CrossRefGoogle Scholar
  5. Cheung WY (1969) Cyclic 3′,5′-nucleotide phosphodiesterase: Preparation of a partially inactive enzyme and its subsequent stimulation by snake venom. Biochim Biophys Acta 191: 303–315CrossRefGoogle Scholar
  6. Cheung WY (1980) Calmodulin plays a pivotal role in cellular regulation. Science 207: 19–27CrossRefGoogle Scholar
  7. Cheung WY, Lynch TJ, Wallace RW (1978) An endogenous Ca2+-dependent activator protein of brain adenylate cyclase and cyclic nucleotide phosphodiesterase. Adv Cyclic Nucleotide Res 9: 233–251PubMedGoogle Scholar
  8. Cheung WY (1982) Role of calmodulin in brain function. In: Gispen WH, Routtenberg A (eds) Progress in brain research. Elsevier, Amsterdam, pp 237–253Google Scholar
  9. Colowick SP, Womack FC (1969) Binding of diffusible molecules by macromolecules: rapid measurement by rate of dialysis. J Biol Chem 244: 774–777PubMedGoogle Scholar
  10. Cox JA, Malnoe A, Stein EA (1981) Regulation of brain cyclic nucleotide phosphodiesterase by calmodulin. J Biol Chem 256: 3218–3222PubMedGoogle Scholar
  11. DeLorenzo RJ (1976) Calcium-dependent phosphorylation of specific synaptosomal fraction proteins: possible role of phosphorylation in mediating neurotransmitter release. Biochem Biophys Res Commun 71: 597–598CrossRefGoogle Scholar
  12. Feldmann K (1978) New devices for flow dialysis and ultrafiltration for the study of protein-ligand interactions. Anal Biochem 88: 225–235CrossRefGoogle Scholar
  13. Fiske CH, SubbaRow Y (1925) The colorimetric determination of phosphorus. J Biol Chem 66: 375–400Google Scholar
  14. Kakiuchi S, Sobue K, Yamazaki R, Kambayashi J, Sakon M, Kosaki G (1981) Lack of tissue specificity of calmodulin: a rapid and high-yield purification method. FEBS Lett 126: 203–207CrossRefGoogle Scholar
  15. Klee CB, Krinks MH (1978) Purification of cyclic 3′,5′-nucleotide phosphodiesterase inhibitory protein by affinity chromatography on activator protein coupled to sepharose. Biochemistry 17: 120–126CrossRefGoogle Scholar
  16. Krüger BK, Forn J, Greengard P (1977) Depolarization-induced phosphorylation of specific proteins, mediated by calcium ion influx, in rat brain synaptosomes. J Biol Chem 252: 2664–2773Google Scholar
  17. Lau YS, Gnegy ME (1980) Effects of lanthanum and trifluoperazine on 125I calmodulin binding to striatal particulates. J Pharmacol Exp Ther 215: 28–34PubMedGoogle Scholar
  18. Lin YM, Liu YP, Cheung WY (1974) Cyclic 3′,5′-nucleotide phosphodiesterase. Purification, characterization, and active form of the protein activator from bovine brain. J Biol Chem 2449: 4943–4954Google Scholar
  19. Lowry OH, Rosebrough NJ, Farr AL, Randall RF (1951) Protein measurement with the folin-phenol-reagent. J Biol Chem 193: 265–275Google Scholar
  20. Means AR, Tash JS, Chafouleas JG (1982) Physiological implications of the presence, distribution, and regulation of calmodulin in eukaryotic cells. Physiol Rev 62: 1–39CrossRefGoogle Scholar
  21. Peterson GL (1977) A simplification of the protein assay method of Lowry et al. which is more generally applicable. Anal Biochem 83: 346–356CrossRefGoogle Scholar
  22. Portzehl H, Caldwell PC, Rüegg JC (1964) The dependence of contraction and relaxation of muscle fibres from the crab Maia Squinado on the internal concentration of free calcium ions. Biochim Biophys Acta 79: 581–591PubMedGoogle Scholar
  23. Teo TS, Wang JH (1973) Mechanism of activation of cyclic adenosine 3',5'-monophosphate phosphodiesterase from bovine heart by calcium ions. J Biol Chem 248: 5950–5955PubMedGoogle Scholar
  24. Teshima Y, Kakiuchi S (1974) Mechanism of stimulation of Ca2+ plus Mg2+-dependent phosphodiesterase from rat cerebral cortex by the modulator protein and Ca2+. Biochem Biophys Res Commun 56: 489–495CrossRefGoogle Scholar
  25. Vandermeers A, Robberecht P, Vandermeers-Pitet MC, Rathe J, Christophe J (1978) Specific binding of the calcium-dependent regulator protein to brain membranes from the guinea pig. Biochem Biophys Res Commun 84: 1076–1081CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • E. Habermann
    • 1
  • K. Crowell
    • 1
  • P. Janicki
    • 1
  1. 1.Rudolf-Buchheim-Institut für Pharmakologie der Justus-Liebig-Universität GiessenGiessenGermany

Personalised recommendations