CHEMBL5738430

Enzymatic Assay: Human full-length FLAG-TEV-ATR and His6-ATRIP were co-expressed in HEK293 cells. The cell pellet (20 g) was harvested and lysed in 100 mL of lysis buffer (20 mM Tris-HCl pH 7.5 at room temperature, 137 mM NaCl, 10% glycerol, 1 mM DTT, 1% (v/v) Tween-20, 0.1% (v/v) NP-40, complete protease inhibitor cocktail tablets, phosphatase inhibitor cocktail tablets, 2 mM MgCl2, 0.2 mM EDTA, and 1 mM ATP). After sonication and centrifugation, the supernatant was incubated at 4° C. for 3 hours with 1 mL of anti-FLAG resin (Sigma catalog #A2220) that had been pre-equilibrated in buffer A (20 mM Tris-HCl pH 7.5 at room temperature, 137 mM NaCl, 10% glycerol, 1 mM DTT, 2 mM MgCl2, and 0.2 mM EDTA). The sample was loaded into a column, and then washed with buffer A three times. Protein was subsequently eluted with 2 ml of buffer B (buffer A+200 g/ml 3×FLAG peptide).