Keep container tightly closed in a dry and well-ventilated place. Recommended storage temperature: 2-8°C. Store under inert gas. Air sensitive

IATA: Hazard Class: 6.1; UN Number: UN2811; Packing Group: III; Shipping Name: Toxic solid, organic, n.o.s. (TBBz)

Zien, P., et al. , Tetrabromobenzotriazole (TBBt) and tetrabromobenzimidazole (TBBz) as selective inhibitors of protein kinase CK2: Evaluation of their effects on cells and different molecular forms of human CK2. Biochim Biophys Acta. 1754, 271-280 (2005). Biochim. Biophys. Acta 1754, 278-280, (2005)

TBBz is a cell-permeable Casein Kinase-2 (CK2) inhibitor. CK2 inhibitors, 4,5,6,7-tetrabromobenzotriazole (TBBt, Sigma Cat. # T0826) and rabromobenzimidazole (TBBz), the latter of which was shown to discriminate between different molecular forms of CK2 in yeast. TBBt, with a pK(a) ~5, exists in solution at physiological pH almost exclusively (>99%) as the monoanion; whereas TBBz, with a pKa ~9, is predominantly (>95%) in the neutral form, both of obvious relevance to their modes of binding. In vitro, TBBt inhibits different forms of CK2 with Ki values ranging from 80 to 210 nM. TBBz discriminates better between CK2 forms, with Ki values ranging from 70-510 nM. TBBz is more effective than TBBt in inducing apoptosis and to a lesser degree, necrosis in transformed human cell lines. Dvelopment of shRNA strategies for the selective knockdown of the CK2α and CK2α′ isoforms reinforces the foregoing results, indicating that inhibition of CK2 leads to attenuation of proliferation.