7Li nuclear-magnetic-resonance study of lithium binding to myo-inositolmonophosphatase.
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.
Saudek
V
V
Marion Merrell Research Institute, Strasbourg, France.
Vincendon
P
P
Do
Q T
QT
Atkinson
R A
RA
Sklenar
V
V
Pelton
P D
PD
Piriou
F
F
Ganzhorn
A J
AJ
D000595:Amino Acid Sequence; D001665:Binding Sites; D002413:Cations, Divalent / Q000378:metabolism; D003001:Cloning, Molecular; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D007672:Kidney Cortex / Q000201:enzymology; D007700:Kinetics; D008094:Lithium / Q000378:metabolism*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D002413:Cations, Divalent; D007527:Isoenzymes; D046911:Macromolecular Substances; D011994:Recombinant Proteins; D008094:Lithium; D010744:Phosphoric Monoester Hydrolases; C021822:myo-inositol-1 (or 4)-monophosphatase