Kinetics of inhibition by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole on calf thymus casein kinase II.
The adenosine analogue 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) is a specific inhibitor for RNA polymerase II transcription in vivo and in vitro [Tamm + Sehgal (1978) Adv. Virus Res. 22, 187-258; Zandomeni & Weinmann (1984) J. Biol. Chem. 259, 14804-14811]. The effect on RNA polymerase II-specific transcription seems to be mediated by its inhibition of nuclear casein kinase II [Zandomeni, Carrera-Zandomeni, Shugar & Weinmann (1986) J. Biol. Chem. 261, 3414-3419]. Inhibition studies indicated that DRB acted as a mixed-type inhibitor with respect to casein and as a competitive inhibitor with respect to the nucleotide phosphate donor substrates. The DRB inhibition constant is 7 microM for the calf thymus casein kinase II, with regard to both ATP and GTP.
Zandomeni
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Comparative Leukemia Studies Unit, New Bolton Center, University of Pennsylvania, Kennett Square 19348.
D000818:Animals; D047388:Casein Kinases; D002417:Cattle; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology*; D007700:Kinetics; D047428:Protein Kinase Inhibitors; D012263:Ribonucleosides / Q000494:pharmacology*; D013950:Thymus Gland / Q000201:enzymology*
D047428:Protein Kinase Inhibitors; D012263:Ribonucleosides; D004004:Dichlororibofuranosylbenzimidazole; D047388:Casein Kinases