Kinetic co-operativity of wheat-germ RNA polymerase II with adenosine 5′-[βγ-imido]triphosphate as substrate
Year: 1988
Type: article
Abstract: A kinetic study of productive RNA chain elongation indicates that adenosine 5'-[beta gamma-imido]triphosphate can serve as substrate in reactions catalysed by purified wheat-germ RNA polymerase II on a poly[d(A-T)] template. However, in contrast with the results obtained with the natural substrate ATP, the double-reciprocal plots, 1/velocity versus 1/[nucleotide], are not linear but characteristic of apparent negative co-operativity. The extent of the kinetic co-operativity is modified when the reactions are conducted in the additional presence of fixed amounts of an alternative substrate such as ATP or inhibitors such as dATP or cordycepin triphosphate. Analogous results are obtained whether the reactions are carried out in the presence of Mg2+ or Mn2+ as the metal ion cofactor. However, the data show that with Mn2+ the RNA polymerase is less specific in substrate recognition than with Mg2+. Tentative kinetic models are proposed to account for the rate measurements.
Source: Biochemical Journal
DOI: 10.1042/bj2520055
Authors: C Job, J M Soulié, D Job
Institution: Centre National de la Recherche Scientifique
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2234892467