Neurochemical Research

, Volume 7, Issue 11, pp 1403–1414 | Cite as

Substrate interactions with brain(Ca+Mg)-ATPase

  • Joseph D. Robinson
Original Articles
  • 12 Downloads

Abstract

ATP hydrolysis by a partially purified (Ca+Mg)-ATPase preparation from rat brain increased with substrate concentration in a biphasic fashion, with apparentKm values of 3 μM and 0.1 mM. Ca-dependent phosphorylation, however, had only a singleKm value, 3 μM. KCl increased ATPase activity in both concentration ranges, but theK0.5 for KCl decreased from 7 mM to 0.3 mM as the ATP concentration was reduced from 1 mM to 10 μM. TheK0.5 for MgCl2 decreased somewhat less, from 3 mM to 0.6 mM with ATP concentrations from 1 mM to 1 μM, but was far lower for steady-state phosphorylation, 0.03 mM. (Ca+Mg)-dependent hydrolysis was not demonstrable with other nucleotide triphosphates or p-nitrophenyl phosphate, and these substances, as well as a reaction product, Pi, were also inhibitors. On the other hand, ADP inhibited at both ATP concentration ranges, and also stimulated dephosphorylation. This pattern of responses to substrate and cations is reminiscent of that of well-characterized transport ATPases, suggesting similar roles and mechanisms.

Keywords

Phosphate Nucleotide MgCl2 Triphosphate ATPase Activity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Robinson, J. D. 1982. Transport ATPases.in Lajtha, A. (ed.) Handbook of Neurochemistry, Plenum Press, New York, in press.Google Scholar
  2. 2.
    Nakamaru, Y. 1968. Magnesium-adenosine triphosphatase activated by a low concentration of calcium in brain microsomes. J. Biochem. 63: 626–631.Google Scholar
  3. 3.
    de Meis, L., Rubin-Altschul, B. M., andMachado, R. D. 1970. Comparative data of Ca2+ transport in brain and skeletal muscle microsomes. J. Biol. Chem. 254: 1883–1889.Google Scholar
  4. 4.
    Robinson, J. D. 1976. (Ca+Mg)-stimulated ATPase activity of a rat brain microsomal preparation. Arch. Biochem. Biophys. 176: 366–374.Google Scholar
  5. 5.
    Saermark, T., andVilhardt, H. 1979. Isolation and partial characterization of magnesium ion- and calcium ion-dependent adenosine triphosphatase activity from bovine brain microsomal fraction. Biochem. J. 181: 321–330.Google Scholar
  6. 6.
    Gill, D. L., Grollman, E. F., andKohn, L. D. 1981. Calcium transport mechanisms in membrane vesicles from guinea pig brain synaptosomes. J. Biol. Chem. 256: 184–192.Google Scholar
  7. 7.
    Sorensen, R. G., andMahler, H. R. 1981. Calcium-stimulated adenosine triphosphatases in synaptic membranes. J. Neurochem. 37: 1407–1418.Google Scholar
  8. 8.
    Robinson, J. D. 1981. Effects of cations on (Ca2++Mg2+)-activated ATPase from rat brain. J. Neurochem. 37: 140–146.Google Scholar
  9. 9.
    Sobue, K., Ichida, S., Yoshida, H., Yamazaki, R., andKariuchi, S. 1979. Occurrence of Ca2+-and modulator protein-activatable ATPase in the synaptic plasma membranes of brain. FEBS Lett. 99: 199–202.Google Scholar
  10. 10.
    Robinson, J. D. 1981. Vanadate inhibition of brain (Ca+Mg)-ATPase. Neurochem. Res. 6: 225–232.Google Scholar
  11. 11.
    Robinson, J. D. 1978. Calcium-stimulated phosphorylation of a brain (Ca+Mg)-ATPase preparation. FEBS Lett. 87: 261–264.Google Scholar
  12. 12.
    Robinson, J. D. 1976. Substrate sites of the (Na++K+)-dependent ATPase. Biochim. Biophys. Acta 429: 1006–1019.Google Scholar
  13. 13.
    Schuurmans Stekhoven, F., andBonting, S. L. 1981. Transport adenosine triphosphatases. Physiol. Rev. 61: 1–76.Google Scholar
  14. 14.
    Rega, A. F., andGarrahan, P. J. 1975. Calcium ion-dependent phosphorylation of human erythrocyte membranes. J. Memb. Biol. 22: 313–327.Google Scholar
  15. 15.
    Jencks, W. P. 1980. The utilization of binding energy in coupled vectorial processes. Adv. Enzymol. 51: 75–106.Google Scholar
  16. 16.
    Robinson, J. D. 1982. Kinetic analyses and the reaction mechanism of the Na, K-ATPase. Curr. Topics Memb. Transport, in press.Google Scholar

Copyright information

© Plenum Publishing Corporation 1982

Authors and Affiliations

  • Joseph D. Robinson
    • 1
  1. 1.Department of PharmacologyState University of New York Upstate Medical CenterSyracuse

Personalised recommendations