Human CDK9 (NP_001252.1, 1 a.a. - 372 a.a.) full-length recombinant protein, N-terminal GST-HIS6 fusion protein with a Thrombin cleavage site and CCNT1 (NP_001231.2, 1 a.a. - 726 a.a.) full-length recombinant protein, N-terminal HIS6 fusion protein with a Thrombin cleavage site co-expressed in Sf9 insect cells.