| Assay Method Information | |
| | JAK1, JAK2, JAK3, and Tyk-2 Enzyme Activity Assays |
| Description: | The activity of JAK3 (a.a. 781-1124, ThermoFisher) was quantified by measuring the phosphorylation of SRCtide (FAM-GEEPLYWSFPAKKK-NH2). Kinase reactions were run in a 384-well Greiner plate with 2% final DMSO concentration under the buffer conditions of 20 mM HEPES, pH 7.5, 10 mM MgCl2, 0.01% BSA, and 0.0005% Tween-20. The kinase reaction components were 2.5 nM JAK3, 1 μM SRCtide peptide and 1 uM ATP. Examples were tested in dose-response starting at 2 M (11 concentrations, 3-fold serial dilution, duplicate reactions). The reactions were incubated at room temperature for 40 minutes, then stopped by adding a 1:1 volume of 30 mM EDTA in 20 mM HEPES, pH 7.5 (15 mM EDTA final). After the reaction was stopped, the phosphorylated and unphosphorylated peptides were separated and quantified using a Caliper LC3000/EZ-Reader system and HTS Well Analyzer Software (Caliper, A PerkinElmer Company, Hopkinton, Mass.). GraFit (Erithacus Software Ltd., Horley, U.K.) was used to calculate inhibitor potency by fitting dose-response data to the 4-parameter logistical IC50 equation.The inhibitory potency of candidate compounds of JAK1, JAK2, and Tyk-2 was done at Thermo Fisher Scientific in their Selectscreen using a Z-lyte assay. Following are the assay details for each enzyme.JAK: The 2×JAK-enzyme/Tyr 06 mixture is prepared in 50 mM HEPES pH 6.5, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA, 0.02% NaN3. The final 10 μL of the Kinase Reaction consists of 21.2-91.5 ng JAK and 2 M Tyr 06 in 50 mM HEPES pH 7.0, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA, 0.01% NaN3. After the one hour Kinase Reaction incubation, 5 μL of a 1:128 dilution of Development Reagent is added.JAK2: The 2×JAK2/Tyr 06 mixture is prepared in 50 mM HEPES pH 7.5, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA. The final 10 μL Kinase Reaction consists of 0.12-0.5 ng JAK2 and 2 M Tyr 06 in 50 mM HEPES pH 7.5, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA. After the one hour Kinase Reaction incubation, 5 μL of a 1:128 dilution of Development Reagent A is added.TYK2: The 2×TYK2/Tyr 03 mixture is prepared in 50 mM HEPES pH 6.5, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA, 0.02% NaN3. The final 10 μL Kinase Reaction consists of 3.75-15 ng TYK2 and 2 M Tyr 03 in 50 mM HEPES pH 7.0, 0.01% BRIJ-35, 10 mM MgCl2, 1 mM EGTA, 0.01% NaN3. After the one hour KinaseReaction incubation, 5 μL of a 1:4096 dilution of Development Reagent A is added.Data reduction for JAK1, JAK2 and TYK2 is done the same, independent of the enzyme run. In summary, background signal is defined in the absence of enzyme and uninhibited signal is defined in the presence of vehicle (2% DMSO) alone. Compounds were evaluated in an 11 point dose-response ranging from 20 mM to 0.34 nM. IC50 values of compounds are determined using a 4 parameter logistical fit of emission ratio as a function of the concentration of compound. |
| Affinity data for this assay | |
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