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Solubilized DNA-dependent RNA polymerase from human placenta: A Mn(2+)-dependent enzyme
H -P. Voigt1, R Kaufmann, H Matthaei
1Arbeitsgruppe Biochemie, Max-Planck-Institut für experimentelle Medizin, 34, Göttingen, Germany
FEBS Letters
|October 16, 1970
Summary
Human placental RNA polymerase requires DNA to function and is most active with Mn(2+) and (NH(4))(2)SO(4). Denatured DNA serves as a superior template, and alpha-amanitin inhibits activity, indicating specific enzyme characteristics.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- RNA polymerase is crucial for gene transcription in eukaryotes.
- Understanding human placental RNA polymerase is important for studying gene expression during pregnancy.
Purpose of the Study:
- To characterize the enzymatic activity and optimal conditions for human placental RNA polymerase.
- To investigate the template preference and inhibitor susceptibility of this enzyme.
Main Methods:
- Purification of RNA polymerase from human placenta.
- Assay of enzymatic activity under varying conditions (cofactors, DNA template types).
- Inhibition studies using alpha-amanitin and rifampicin.
Main Results:
- Purified enzyme shows complete DNA dependence.
- Optimal activity observed with 3 mM Mn(2+) and 100 mM (NH(4))(2)SO(4).
- Denatured DNA is a more effective template than native DNA; alpha-amanitin confirmed inhibition, while rifampicin showed no effect.
Conclusions:
- Human placental RNA polymerase exhibits specific cofactor and template requirements.
- The enzyme's sensitivity to alpha-amanitin suggests it is an RNA polymerase II or a related enzyme.
- Rifampicin resistance indicates it is not bacterial RNA polymerase.