Assay Method Information

Assay Name:  Measurement of FXIa Inhibition
Description:  To determine the factor XIa inhibition of the substances according to the invention, a biochemical test system is used which utilizes the reaction of a peptidic factor XIa substrate to determine the enzymatic activity of human factor XIa. Here, factor XIa cleaves from the peptic factor XIa substrate the C-terminal aminomethylcoumarin (AMC), the fluorescence of which is measured. The determinations are carried out in microtitre plates.Test substances are dissolved in dimethyl sulphoxide and serially diluted in dimethyl sulphoxide (3000 μM to 0.0078 μM; resulting final concentrations in the test: 50 μM to 0.00013 μM). In each case 1 μl of the diluted substance solutions are placed into the wells of white microtitre plates from Greiner (384 wells). 20 μl of assay buffer (50 mM of Tris/HCl pH 7.4; 100 mM of sodium chloride solution; 5 mM of calcium chloride solution; 0.1% of bovine serum albumin) and 20 μl of factor XIa from Kordia (0.45 nM in assay buffer) are then added successively. After 15 min of incubation, the enzyme reaction is started by addition of 20 μl of the factor XIa substrate Boc-Glu(OBzl)-Ala-Arg-AMC dissolved in assay buffer (10 μM in assay buffer) from Bachem, the mixture is incubated at room temperature (22° C.) for 30 min and fluorescence is then measured (excitation: 360 nm, emission: 460 nm). The measured emissions of the test batches with test substance are compared to those of control batches without test substance (only dimethyl sulphoxide instead of test substance in dimethyl sulphoxide), and the IC50 values are calculated from the concentration/activity relationships.
Affinity data for this assay
 

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