Kalii Dehydrographolidi Succinas (Dehydroandrographolide Succinate Potasium Salt) is a natural compound with anti-virus infection activity.

In vitro kinase assay is based on a filter binding assay, using the recombinant GST-fused kinase domains expressed in baculovirus and purified over glutathione-sepharose, γ-[33P]ATP as the phosphate donor, and poly(Glu:Tyr 4:1) peptide as the acceptor. Each GST-fused kinase is incubated under optimized buffer conditions [20 mM Tris-HCl buffer (pH 7.5), 1-3 mM MnCl2, 3-10 mM MgCl2, 3-8 μg/mL poly(Glu:Tyr 4:1), 0.25 mg/mL polyethylene glycol 20000, 8 μM ATP, 10 μM sodium vanadate, 1 mM DTT] and 0.2 μCi γ-33P ATP in a total volume of 30 μL in the presence or absence of a test substance for 10 min at ambient temperature. The reaction is stopped by adding 10 mL of 250 mM EDTA. Using a 384-well filter system, half the volume is transferred onto an Immobilon-polyvinylidene difluoride membrane. The membrane is then washed extensively and dried, and scintillation counting is performed. IC50s for compounds are calculated by linear regression analysis of the percentage inhibition[1].