1-EBIO (1-EBIO) is a calium channel agonist.

Procedures for BTK OMNIA Assay: The Omnia continuous read assay is performed essentially as described by the vendor. The assay conditions are: 40 μM ATP (1X KMATP), 10 μM Y5-Sox, and 10 nM BTK enzyme. Briefly, a substrate mix containing 1.13X ATP and the Y5 Sox substrate is first prepared in 1X Omnia Kinase Reaction Buffer (KRB) consisting of 20 mM Tris, pH 7.5, 5 mM MgCl2, 1 mM EGTA, 5 mM?β-glycerophosphate, 5% glycerol, and 0.2 mM DTT. For IC50 measurements, 5 μL of enzyme are incubated with serially diluted (3-fold) compounds prepared in 50% DMSO in a Corning (#3574) 384-well, white, non-binding surface microtiter plate at 25°C for 30 min. Kinase reactions are started with the addition of 45 μL of the ATP/Y5 substrate mix and monitored at λex360/λem485 in a Synergy 4 plate reader for 60 minutes. Progress curves from each well are examined for linear reaction kinetics and fit statistics. Initial velocity from each reaction is determined from the slope of a plot of relative fluorescence units versus time and then plotted against inhibitor concentration to estimate IC50 using the Response, Variable Slope model in GraphPad Prism from GraphPad Software.