Table I.
Binding affinity and Bmax of AT2 receptor orthologues
| [Sar1,Ile8]Ang II, (Ki, nM) |
CGP42112A, (Ki, nM) |
PD123319, (Ki, nM) |
Bmax, (pmol/mg) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Control | DTT (5mM) | -fold | Control | DTT (5mM) | -fold | Control | DTT (5mM) | -fold | Control | DTT (5mM) | -fold | |
| rbAT2 | 0.89±0.15 | 0.09±0.02 | 9.89 | 0.61±0.13 | 0.07±0.01 | 8.71 | 17.7±2.2 | 2.4±0.43 | 7.38 | 4.05±0.35 | 0.85±0.38 | 4.765 |
| rAT2 | 0.82±0.14 | 0.08±0.01 | 10.3 | 0.65±0.11 | 0.07±0.01 | 9.29 | 17.2±2.5 | 2.1±0.37 | 8.19 | 4.11±0.32 | 3.95±0.34 | 1.041 |
| mAT2 | 0.83±0.12 | 0.08±0.01 | 10.4 | 0.63±0.10 | 0.08±0.01 | 7.88 | 18.4±2.8 | 2.5±0.31 | 7.36 | 4.08±0.36 | 4.09±0.41 | 0.998 |
| hAT2 | 0.87±0.11 | 0.09±0.01 | 9.67 | 0.57±0.09 | 0.07±0.01 | 8.14 | 16.7±2.6 | 2.3±0.36 | 7.26 | 3.93±0.33 | 3.91±0.37 | 0.995 |
| rbAT2N | 2.98±0.76 | 0.11±0.02 | 27.1 | 0.69±0.12 | 0.08±0.01 | 8.63 | 17.6±2.3 | 2.3±0.38 | 7.69 | 3.78±0.32 | 0.62±0.35 | 6.096 |
Cell membranes were pre-treated with and without 5mM DTT at 22°C for 20 minutes. Here rbAT2, rAT2, mAT2, and hAT2 represent rabbit, rat, mouse, and human AT2 receptor orthologues, respectively. The rbAT2N is a rbAT2 mutant with deletion of the first 33 amino acids. This mutant is very similar to the wild type rbAT2 except for a reduced binding affinity (3.3 fold) for [Sar1,Ile8]Ang II in the absence of DTT treatment. Data represent results of three or more experiments of binding isotherms followed by Scatchard analysis. Results are presented as mean ± s.e.m.