S. Sarno et al., Selectivity of 4,5,6,7-tetrabromobenzotriazole, an ATP site-directed inhibitor of protein kinase CK2 ('casein kinase-2'), FEBS LETTER, 496(1), 2001, pp. 44-48
The specificity of 4,5,6,7-tetrabromo-2-azabenzimidazole (TBB), an ATP/GTP
competitive inhibitor of protein kinase casein kinase-2 (CK2), has been exa
mined against a panel of 33 protein kinases, either Ser/Thr- or Tyr-specifi
c, In the presence of 10 muM TBB land 100 muM ATP) only CK2 was drastically
inhibited (> 85%) whereas three kinases (phosphorylase kinase, glycogen sy
nthase kinase 3 beta and cyclin-dependent kinase 2/cyclin A) underwent mode
rate inhibition, with IC50, values one-two orders of magnitude higher than
CK2 (IC50 = 0.9 muM). TBB also inhibits endogenous CK2 in cultured Jurkat c
ells. A CK2 mutant in which Val66 has been replaced by alanine is much less
susceptible to inhibition by TBB as well as by another ATP competitive inh
ibitor, emodin, These data show that TBB is a quite selective inhibitor of
CK2, that can be used in cell-based assays. (C) 2001 Published by Elsevier
Science B,V, on behalf of the Federation of European Biochemical Societies.