TY - JOUR
T1 - Glucose binding isotope effects in the ternary complex of brain hexokinase demonstrate partial relief of ground-state destabilization
AU - Lewis, Brett E.
AU - Schramm, Vern L.
PY - 2003/4/23
Y1 - 2003/4/23
N2 - Isotope effects can yield detailed information about contacts made between a bound compound and its host receptor or enzyme. In this study, we have measured isotope effects upon the equilibrium constant for the association of glucose and human brain hexokinase [E.C.2.7.1.1] in the presence of β,γ-CH2-ATP and compared these with data for the same equilibrium in the absence of ATP-analogue. We have found isotope effects of 1.012, 0.929, 1.031, 1.052, 0.998, and 1.032 for the competitive binding of [1-3H]-, [2-3H]-, [3-3H]-, [4-3H]-, [5-3H]-, or [6,6-3H2]- and either [2-14C]- or [6-14C]glucose to brain hexokinase. We observed changes only at H1, H5, and H6, and we attribute these to a slight change in the position of Asn683 and Glu742 due to nucleotide binding and to partial satisfaction of activated OH6 by the terminal nucleotide phosphorus.
AB - Isotope effects can yield detailed information about contacts made between a bound compound and its host receptor or enzyme. In this study, we have measured isotope effects upon the equilibrium constant for the association of glucose and human brain hexokinase [E.C.2.7.1.1] in the presence of β,γ-CH2-ATP and compared these with data for the same equilibrium in the absence of ATP-analogue. We have found isotope effects of 1.012, 0.929, 1.031, 1.052, 0.998, and 1.032 for the competitive binding of [1-3H]-, [2-3H]-, [3-3H]-, [4-3H]-, [5-3H]-, or [6,6-3H2]- and either [2-14C]- or [6-14C]glucose to brain hexokinase. We observed changes only at H1, H5, and H6, and we attribute these to a slight change in the position of Asn683 and Glu742 due to nucleotide binding and to partial satisfaction of activated OH6 by the terminal nucleotide phosphorus.
UR - http://www.scopus.com/inward/record.url?scp=0037462109&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037462109&partnerID=8YFLogxK
U2 - 10.1021/ja029852k
DO - 10.1021/ja029852k
M3 - Article
C2 - 12696861
AN - SCOPUS:0037462109
SN - 0002-7863
VL - 125
SP - 4672
EP - 4673
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 16
ER -