Kinase experiment:

Monoiodinated 125I-[Sar1,Leu8]angiotensin II is prepared by the Iodo-Gen method. One day after transfection and 24 hr before the binding experiments, the transfected cells are transferred to 6-, 12-, or 24-well culture plates, with 0.15-9 × 105 cells/well, with a goal of total binding of 5-10% of the radiolabeled peptide. The cells are washed twice with buffer (25 mM Tris, 5 mM MgCl2, 140 mM NaCl, pH 7.4) before and after the binding. The binding is carried out for 24 hr at 4℃ with 50 pm 125I-[Sar1,Leu8]angiotensin II and variable amounts of unlabeled nonpeptide or peptide ligands in 0.5-1 mL of a 25 mM Tris buffer containing 5 mm MgCl2, pH 7.4. The binding data are analyzed by computerized nonlinear regression analysis using InPlot 4.0.

L162389 is a potent antagonist of angiotensin AT1 receptor with Ki of 28 nM.

L-162,389 stimulates phosphatidylinositol turnover, albeit only to a small percentage of the angiotensin response. L-162,389 acts as angiotensin antagonist with IC50 value of 105 nM[1].

[1]. Perlman S, et al. Dual agonistic and antagonistic property of nonpeptide angiotensin AT1 ligands: susceptibility to receptor mutations. Mol Pharmacol. 1997 Feb;51(2):301-11.