Highly selective affinity libeling of human placenta DNA-dependent RNA polymerase

T. G. Maximova, A. A. Mustaev, E. F. Zaychikov, A. V. Polukhin, V. K. Reit

Limnological Institute, Siberian Division, Academy of Sciences of the USSR, Irkutsk; Novosibirsk State University, Novosibirsk

Abstract: RNA polymerase II from human placenta was affinity labelled in crude preparation using two-step technique, which includes treatment of the enzyme with an aldehyde-containing reactive analogue of ATP, ADP or AMP in the presence of poly[d(AT)] followed (after borohydride reduction) by the elongation of the attached label with [α-32P]UTP. A polypeptide of the molecular mass ca. 140 kDa proved to be the labelling target. No labelling was observed in the absence of poly[d(AT)] or the reagent or in the presence of a-amanitin. All the results suggest the attachment of the affinity reagents to the second-largest subunit of the human RNA polymerase II, which therefore takes part in the initiation substrate's binding.

Russian Journal of Bioorganic Chemistry 1990, 16 (8):1145-1148

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