HTRF MAb Anti GST-Eu cryptate Kinase Binding Kit, 1,000 Assay Points

Kd determination assay principal

​The binding of the tracers is detected in a sandwich assay format using the Anti GST antibody labeled with Europium Cryptate (donor), which binds to the GST-tagged Kinase, and a red fluorescent tracer labelled with d2 (acceptor). The detection principle is based on HTRF® technology. The HTRF ratio (665/620) will increase upon the addition of more of the tracer, and will saturate depending on the dissociation constant (Kd) of the tracer to the GST-tagged kinase.

Kd determination assay protocol

Saturation binding experiments on the three tracers (i.e. Staurosporine-Red, Dasatinib-Red, and Sunitinib-Red) can be run in 96- or 384-well plates (20 µL final volume). First, a dilution series of tracer ranging between 0 and 1 µM in the Kinase Binding Buffer is prepared in a 96-well non-binding plate. Next, 5 µL of Kinase Binding Buffer are dispensed into the final 96- or 384-well plate. Then 5 µL of GST tagged-Kinase are added, followed by 5 µL of Anti-GST Eu-cryptate. Finally, 5 µL of the red tracer solution are added. The HTRF ratio is measured after 1 H of incubation.

IC50/Ki determination assay principle

The binding of the tracers is detected in a sandwich assay format using the Anti-GST labeled with Europium Cryptate (donor), which binds to the tagged Kinase, and a red fluorescent tracer labelled with d2 (acceptor). The detection principle is based on HTRF® technology. The HTRF ratio (665/620) will increase upon the addition of more of the tracer, and will saturate depending on the dissociation constant (Kd ) of the tracer to the tagged kinase. When an inhibitor of the kinase is added, the tracer will be displaced and the HTRF signal will disappear, depending on the dose.

IC50/Ki determination assay protocol

​Pharmacological evaluation of inhibitors of interest can be run in 96- or 384-well plates. First, a dilution series of inhibitor ranging between 40 µM and 0.23 nM is prepared, and 5 µL of each concentration are dispensed into the plate. Next, 5 µL of tagged-Kinase are added, followed by 5 µL of anti-GST Eu-cryptate. Finally, 5 µL of tracer solution are added, prepared at 4x the final concentration. The HTRF ratio is measured after 1H of incubation. Analyses of the data give typical dose response curves ranging between 10 µM and 56 pM, enabling an evaluation of the IC50/Ki values for the inhibitor of interest.