Membranes | |
KDH(pM) | 48.9 ± 7.3 |
BmaxH (fmol/mg protein) | 554.3 ± 24.9 |
% Total | 21.0 |
KDL (nM) | 14.7 ± 4.3 |
BmaxL (pmol/mg protein) | 2.07 ± 0.13 |
% Total | 79.0 |
Whole cells | |
KDH (pM) | 288.0 |
BmaxH | 3,493 receptors/cell, (94 fmol/mg protein1-a) |
% Total | 18.8 |
KDL(nM) | 12.8 |
BmaxL | 15,057 receptors/cell, (425 fmol/mg protein1-a) |
% Total | 81.2 |
Binding parameters were determined as described in “Methods.” All values for the membrane-based assay represent the mean ± S.E.M. of three to four experiments all carried out in duplicate or triplicate. For the whole cell saturation isotherm, a composite, nonlinear regression analysis of data from three independent experiments was required to adequately determine the low affinity component. Data from both membranes and whole cells were best fit by a two-state/two-site model (P < .05).
↵1-a Bmax values from the whole cell saturation isotherm were expressed conventionally as receptors/cell, but also as fmol/mg protein assuming a membrane protein yield of 60 μg/106 GALR1 HEK293E cells.