TY - JOUR
T1 - Fluorescence decay time measurements of Eu3+-ATP-enzyme complexes. Replacement of the metal hydration water by active site ligands.
AU - Gutman, M.
AU - Levy, M. A.
PY - 1983/10/25
Y1 - 1983/10/25
N2 - Measurements of the fluorescent lifetimes of the rare earth metal Eu3+ in varying mole fractions of H2O/D2O were used to determine the hydration of the metal in the presence of ATP and/or hexokinase or chloroplast reversible ATPase. The number of water molecules coordinated to the metal in Eu3+-ATP was estimated to be 2.6; when this complex is bound to hexokinase, 1 water molecule is displaced. Upon binding to chloroplast reversible ATPase, the metal coordinates 1 water molecule while the Eu3+-ATP complex does not retain any associated solvent. These numbers are in contrast to the 9 solvent molecules coordinated to the naked metal ion. These results are discussed in reference to mechanistic and structural considerations of the two enzymes.
AB - Measurements of the fluorescent lifetimes of the rare earth metal Eu3+ in varying mole fractions of H2O/D2O were used to determine the hydration of the metal in the presence of ATP and/or hexokinase or chloroplast reversible ATPase. The number of water molecules coordinated to the metal in Eu3+-ATP was estimated to be 2.6; when this complex is bound to hexokinase, 1 water molecule is displaced. Upon binding to chloroplast reversible ATPase, the metal coordinates 1 water molecule while the Eu3+-ATP complex does not retain any associated solvent. These numbers are in contrast to the 9 solvent molecules coordinated to the naked metal ion. These results are discussed in reference to mechanistic and structural considerations of the two enzymes.
UR - http://www.scopus.com/inward/record.url?scp=0021112705&partnerID=8YFLogxK
U2 - 10.1016/s0021-9258(17)44144-5
DO - 10.1016/s0021-9258(17)44144-5
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C2 - 6226653
AN - SCOPUS:0021112705
SN - 0021-9258
VL - 258
SP - 12132
EP - 12134
JO - The Journal of biological chemistry
JF - The Journal of biological chemistry
IS - 20
ER -