7Li nuclear-magnetic-resonance study of lithium binding to myo-inositolmonophosphatase

Eur J Biochem. 1996 Aug 15;240(1):288-91. doi: 10.1111/j.1432-1033.1996.0288h.x.


The interaction of Li+ with myo-inositol monophosphatase was studied by 7Li-NMR spectroscopy. Li+ binding to the enzyme induces a downfield shift and broadening of the 7Li-NMR signal. Changes of the chemical shift were used to follow the titration of the enzyme with lithium and to determine a dissociation constant, Kd = (1.0 +/- 0.1) mM. Only one major binding site/enzyme subunit was inferred. The complex forms independently of the presence of inorganic phosphate. Metals from the group IIa of the periodic table compete with Li+ binding with the affinity increasing in the order Mg2+ < Ca2+ < Be2+. In contrast to lithium, their binding is enhanced by phosphate.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Cations, Divalent / metabolism
  • Cloning, Molecular
  • Humans
  • Isoenzymes / chemistry
  • Isoenzymes / metabolism
  • Kidney Cortex / enzymology
  • Kinetics
  • Lithium / metabolism*
  • Macromolecular Substances
  • Magnetic Resonance Spectroscopy / methods
  • Phosphoric Monoester Hydrolases / chemistry*
  • Phosphoric Monoester Hydrolases / metabolism*
  • Protein Binding
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism


  • Cations, Divalent
  • Isoenzymes
  • Macromolecular Substances
  • Recombinant Proteins
  • Lithium
  • Phosphoric Monoester Hydrolases
  • myo-inositol-1 (or 4)-monophosphatase