Notes: The authors of this paper demonstrate the utility of the HaloTag^® protein purification system for purifying functional proteins from mammalian cells. To this end five kinases were cloned into HaloTag^® vectors, expressed in and purified from HEK293T cells. To demonstrate functionality of the purified recombinant kinases, activity was measured using the appropriate ADP-Glo™ Assay Kinase Enzyme Systems. (4145)