Ki: 0.5-1 μM

4,5,6,7-Tetrabromobenzimidazole is a CK2 inhibitor.

Casein kinase 2 (CK2), a constitutive protein kinase involved in many signal transduction pathways, is known to be able to negatively regulate apoptosis, and its activity is increased in various proliferating tissues and tumors.

In vitro: Previous study found that like the reported 4,5,6,7-tetrabromobenzotriazole (TBBt), the structurally related 4,5,6,7-tetrabromobenzimidazole (TBBz) was a selective ATP-competitive inhibitor of protein kinase CK2 from various sources including yeast, rat liver, Neurospora crassa and Candida tropicalis, with K(i) values in the range 0.5-1 μM. TBBz was found to virtually inactive vs. PKA, PKC, and a very weak inhibitor of protein kinase CK1. TBBt was noted to be a more effective inhibitor of PK60S than of yeast CK2; by contrast, TBBz was a relatively feeble inhibitor of PK60S, thus more selective than TBBt vs. CK2 in yeast cells. Therefore, similar to TBBt, TBBz could be regarded as an additional lead compound for development of more potent inhibitors of CK2 [1].

In vivo: Up to now, therer is no animal in vivo data reported.

Clinical trial: So far, no clinical study has been conducted.

Reference:
[1] Zien, P. ,Bretner, M.,Zastapilo, K., et al. Selectivity of 4,5,6,7-tetrabromobenzimidazole as an ATP-competitive potent inhibitor of protein kinase CK2 from various sources. Biochemical and Biophysical Research Communications 306(1), 129-133 (2003).