Complex of recombinant human cyclin dependent kinase 9 (CDK9), also known as cell division protein kinase 9, and recombinant human cyclin T1 (CCNT1, CycT1). The CDK9 construct is full length, encompassing amino acids 2-372(end), with N-terminal GST-tag. The cyclin T1 construct is full length, encompassing amino acids 2-726(end), with N-terminal GST-tag. The recombinant proteins were co-expressed and affinity purified.