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Volume 240, Issue 1 p. 288-291
Free Access

7Li Nuclear-Magnetic-Resonance Study of Lithium Binding to Myo-Inositol Monophosphatase

Vladimir Saudek

Vladimir Saudek

Marion Merrell Research Institute, Strasbourg, France

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Pascale Vincendon

Pascale Vincendon

Marion Merrell Research Institute, Strasbourg, France

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Quoc-Tuan Do

Quoc-Tuan Do

Marion Merrell Research Institute, Strasbourg, France

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R. Andrew Atkinson

R. Andrew Atkinson

Marion Merrell Research Institute, Strasbourg, France

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Vladimir Sklenár

Vladimir Sklenár

Marion Merrell Research Institute, Strasbourg, France

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Patricia D. Pelton

Patricia D. Pelton

Marion Merrell Research Institute, Strasbourg, France

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François Piriou

François Piriou

Marion Merrell Research Institute, Strasbourg, France

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Axel J. Ganzhorn

Corresponding Author

Axel J. Ganzhorn

Marion Merrell Research Institute, Strasbourg, France

Correspondence to A. J. Ganzhorn, Marion Merrell Research Institute, 16 Rue d'Ankara, F-67080 Strasbourg Cedex, France
Fax: +33 88 45 90 75.Search for more papers by this author
First published: August 1996
Citations: 18

Abstract

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.

Abbreviations

  • δ
  • chemical shift in parts per million (ppm) or parts per billion (ppb)
  • d
  • chemical shift of Li+ complexed to the enzyme (limiting value in the titrations)
  • Enzymes

  •  
  • myo -Inositol-1(or 4)-monophosphatase (EC 3.1.3.25)