| Assay Method Information | |
| | Factor XIIa (FXIIa) Inhibitory Activity |
| Description: | In a 96-well clear bottom plate, 80 μl of assay buffer was added to each well. Assay buffer consists of 0.5× Hank's Balanced Salt Solution (Invitrogen), buffered with 25 mM HEPES pH 7.4 (Invitrogen) and 0.5× Tris-buffered saline with Tween-20 0.05% (Santa Cruz Biotechnology). Test compounds were first dissolved in DMSO (Sigma) and then 4 μl were added to test wells containing assay buffer. Serial dilutions using an automated multi-channel pipette were used to generate a concentration range of approximately 1-100 μM. Human FXIIa (Enzyme Research Labs) was diluted in assay buffer to a final concentration of 12.5 nM. 80 μl of this enzyme solution was added to the assay wells. The enzyme/compound mixtures were incubated for 10 minutes at room temperature. Chromogenic substrate (Pefachrome XIIa; Enzyme Research Labs) was added to assay wells at a final concentration of 400 μM. The assay plate was spun for 1 minute at 1500 g and then read at 37° C. in a SpectraMax M2 plate reader (λ=405 nm). Activity was quantified as the rate of change in absorbance, which corresponds to the rate of substrate cleavage. IC50 values were determined as the concentration of inhibitor that produced 50% of the rate of change of control wells without any inhibitor. For compounds with activity <1 μM, the assay was repeated with a lower concentration range, typically from 10-1000 nM. |
| Affinity data for this assay | |
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