Selectivity of 4,5,6,7-tetrabromobenzotriazole, an ATP site-directed inhibitor of protein kinase CK2 ('casein kinase-2')

FEBS Lett. 2001 May 4;496(1):44-8. doi: 10.1016/s0014-5793(01)02404-8.


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 examined against a panel of 33 protein kinases, either Ser/Thr- or Tyr-specific. In the presence of 10 microM TBB (and 100 microM ATP) only CK2 was drastically inhibited (>85%) whereas three kinases (phosphorylase kinase, glycogen synthase kinase 3 beta and cyclin-dependent kinase 2/cyclin A) underwent moderate inhibition, with IC(50) values one--two orders of magnitude higher than CK2 (IC(50)=0.9 microM). TBB also inhibits endogenous CK2 in cultured Jurkat cells. A CK2 mutant in which Val66 has been replaced by alanine is much less susceptible to inhibition by TBB as well as by another ATP competitive inhibitor, emodin. These data show that TBB is a quite selective inhibitor of CK2, that can be used in cell-based assays.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate*
  • Amino Acid Substitution
  • Binding Sites / drug effects
  • Binding Sites / genetics
  • Binding, Competitive / drug effects
  • Casein Kinase II
  • Emodin / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Jurkat Cells / cytology
  • Jurkat Cells / drug effects
  • Jurkat Cells / metabolism
  • Protein Kinases / drug effects
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Staurosporine / pharmacology
  • Substrate Specificity
  • Triazoles / metabolism
  • Triazoles / pharmacology*


  • 4,5,6,7-tetrabromobenzotriazole
  • Enzyme Inhibitors
  • Triazoles
  • Adenosine Triphosphate
  • Protein Kinases
  • Casein Kinase II
  • Protein-Serine-Threonine Kinases
  • Staurosporine
  • Emodin