CDK7 Protein, Human, Recombinant (His)TFIIH basal transcription factor complex kinase subunit, STK1, Serine/threonine-protein kinase 1, MO15, Cyclin-dependent kinase 7, Cell division protein kinase 7, CDKN7, CDK-activating kinase 1, CDK7, CAK1, CAK, 39 kDa protein kinase (p39 Mo15)