Nucleotide binding to creatine kinase: an isothermal titration microcalorimetry study

FEBS Lett. 1999 Nov 12;461(1-2):111-4. doi: 10.1016/s0014-5793(99)01431-3.

Abstract

We investigated the binding of ATP in the presence and absence of Mg(2+) to dimeric muscle creatine kinase (CK) by isothermal titration microcalorimetry as a function of pH and temperature. The thermodynamic parameters for these events show that (1) binding of nucleotide to the CK active site does not involve proton exchange with the buffer and (2) the active sites are the only nucleotide binding sites on CK. Interdependence of the active sites in the dimer could not be demonstrated. As CK undergoes major structural changes upon Mg-nucleotide binding, a thermodynamic cycle was employed to calculate the contributions of domain movements to the observed enthalpies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Calorimetry / methods
  • Chickens
  • Creatine Kinase / metabolism*
  • Magnesium / metabolism
  • Nucleotides / metabolism*
  • Recombinant Proteins / metabolism
  • Temperature
  • Thermodynamics
  • Time Factors

Substances

  • Nucleotides
  • Recombinant Proteins
  • Creatine Kinase
  • Magnesium