cis- and trans-Allostery in wtGLUT1
(●) and GLUT1Q282A (○).
A, cis-allostery. Concentration dependence of
maltose modulation of 2DG influx is shown. Normalized 2DG uptake
(vi/vc) is plotted
as a function of [maltose] (mm) on a log scale. The
curves drawn through the points (solid
lines for wtGLUT1 (●) and dashed lines for
GLUT1Q282A (○)) were computed by nonlinear regression
using Equation 2 and have the
following constants: wtGLUT1 (●), K1 = 0.0028, K2 = 0.31
mm−1, K3 = 0.197 mm−1,
K4 = 1.62 mm−2, R2 =
0.582, standard error of regression = 0.147; GLUT1Q282A (○),
K1 = 0.028, K2 = 1.83 mm−1, K3 = 1.911
mm−1, K4 = 1.62 mm−2,
R2 = 0.582, standard error of regression =
0.147. B, trans-allostery. Concentration
dependence of CB modulation of 2DG influx is shown. Normalized 2DG uptake
(vi/vc) is plotted
as a function of [CB] (μm) on a log scale. The
curves drawn through the points (solid
lines for wtGLUT1 (●) and dashed lines for
GLUT1Q282A (○)) were computed by nonlinear regression
using Equation 2 and have the
following constants: wtGLUT1 (●), K1 = 0.0041
μm2, K2 = 0.073 μm, K3 = 2 ×
10−12 μm, K4 = 1.64,
R2 = 0.637, standard error of regression =
0.179; GLUT1Q282A (○), K1 = 0.0050
μm2, K2 = 0.039 μm, K3 = 8.3 ×
10−14 μm, K4 = 1.495,
R2 = 0.849, standard error of regression =
0.067.