Assay Method Information

Assay Name:  In Vitro Assay
Description:  SYK tyrosine phosphorylation activity is measured using the LANCE Technology developed by Perkin Elmer Life and Analytical Sciences (Boston, Mass.). LANCE refers to homogeneous time resolved fluorometry applications using techniques such as time-resolved fluorescence resonance energy transfer assay (TR-FRET) (see generally for procedures in Perkin Elmer Application Note How to Optimize a Tyrosine Kinase Assay Using Time Resolved Fluorescence-Based LANCE Detection, wwww.perkinelmer.com/lifesciences). The assay principle involves detection of a phosphorylated substrate using energy transfer from a phosphospecific europium-labeled antibody to streptavidin-allophycocyanin as an acceptor.To test the ability of candidate molecules to inhibit SYK tyrosine phosphorylation activity, molecules are reconstituted in 30% DMSO and serially diluted 1:3 with the final dilution containing DMSO in the absence of the candidate molecule. The final DMSO concentration in the assay is 3%. Kinase assays are performed as a two part reaction. The first reaction is a kinase reaction and which comprises of a candidate molecule, full length active recombinant SYK enzyme (Millipore, CA) and biotin-labeled SYK-specific substrate biotin-DEEDYESP-OH. The second reaction involves termination of the kinase reaction and the simultaneous addition of the detection reagents-europium-labeled anti-phosphotyrosine reagent (Eu-W1024-PY100, Perkin Elmer, Boston, Mass.) and Streptavidin-Allophycocyanin detection reagent (SA-APC, Prozyme, CA). The kinase reaction is performed in a black U-bottom 96-well microtitre plate. The final reaction volume is 50 μL and contains a final concentration of 1 nM active SYK enzyme, 550 nM SYK-substrate, and 100 μM ATP diluted in a buffer containing 50 mM Tris pH 7.5, 5 mM MgCl2, and 1 mM DTT. The reaction is allowed to proceed for 1 hour at room temperature. The quench buffer contains 100 mM Tris pH 7.5, 300 mM NaCl2, 20 mM EDTA, 0.02% Brij35, and 0.5% BSA. The detection reagents are added to the reaction mixture at the following dilutions 1:500 for Eu-W1024-PY100 and 1:250 for SA-APC. The kinase reaction is terminated by the addition of 50 μL quench buffer containing the detection reagents. The detection is allowed to proceed for 1 hr at room temperature.
Affinity data for this assay
 

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