| Assay Method Information | |
| | Biotin Assay |
| Description: | A streptavidin-coated plate (Thermo Scientific, NUNC #436014) was washed three times with 300 μL of PBS-0.05% Tween solution. A biotinylated twenty-six amino acid peptide, corresponding to the BH3 domain of Bim, with the sequence biotin-(β)A-D-M-R-P-E-I-W-I-A-Q-E-L-R-R-I-G-D-E-F-N-A-Y-Y-A-R-R-amide (SEQ ID No. 14), hereafter referred to as biotin-Bim, was obtained (Tufts). The biotin-Bim peptide was diluted to 0.018 μg/mL (5 nM) in SuperBlock blocking buffer in PBS (Thermo Scientific, #37515), and 100 μL of this solution was incubated in the streptavidin-coated plate for 2.5 hours while shaking. Separately, a compound of Formula I or Formula II, which had been prepared in a 10 mM stock DMSO solution, was then incubated with 20 nM GST-Mcl-1 fusion protein in PBS. Compounds were tested in six three-fold dilutions ranging from 20 μM to 0.6 μM, 10 μM to 0.3 or 5 μM to 0.15 μM. In addition, Bim peptide (New England Peptide) was utilized as a control and tested in six-fold dilutions ranging from 100 nM to 3.3 nM. The streptavidin-coated plate which had previously been treated with biotin-Bim peptide was then washed three times with 300 μL of PBS-0.05% Tween solution. A solution of GST-MCL-1 and a compound of Formula I or Formula II (100 μL) was then added to the streptavidin-coated plate, with two wells utilized as controls (PBS buffer only, no GST-MCL-1 or biotin-Bim) and two wells as an alternative control (containing GST-MCL-1 but no biotin-Bim), and four three-fold dilutions of DMSO (0.2%, 0.06%, 0.02%, and 0.008%). All wells containing compounds of Formula I or Formula II were loaded in duplicate. The plate was incubated for 2 hours at RT, then washed three times with 300 μL of PBS-0.05% Tween solution. Anti-GST HRP (GE Healthcare, #RPN1236) is diluted 1:20,000 in freshly prepared PBS, 0.1% Tween20, and 0.5% BSA was then added to the plate and the plate was incubated for 30 minutes. The plate was then washed five times with 300 μL of PBS-0.05% Tween solution. A solution of color reagents A (stabilized peroxide solution) and B (stabilized chrommogen solution) (R&D Systems, #DY999) is mixed in a 1:1 ratio and added to each well in a quantity of 80 μL. The wells were allowed to develop until control wells containing DMSO are blue (approximately 5-10 minutes). A solution of ELISA stop solution (1M sulfuric acid, 20 μL per well) was then added. Absorbance at 450 nM was read on a Tecan GeniosPro plate reader. |
| Affinity data for this assay | |
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