A cell-permeable, selective inhibitor of casein kinase-2 (CK2) (IC50 = 0.9 and 1.6 μM for rat liver and human recombinant CK2 respectively). Exhibits modest discrimination between CK2 subunits, with Ki values ranging from 80 nM to 210 nM. Acts in an ATP/GTP-competitive manner and displays one to two orders of magnitude selectivity over a panel of 33 protein kinases. Purity 99%. MW (observed): 434.71