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ISOLATION AND CHARACTERIZATION OF DNA‐DEPENDENT RNA POLYMERASE A, B AND C FROM RAT BRAIN NUCLEI 1
Author(s) -
Yamamoto H.,
Takahashi Y.
Publication year - 1978
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1978.tb02660.x
Subject(s) - enzyme , rna , biochemistry , dna , polymerase , biology , rna polymerase , microbiology and biotechnology , deoxyribonuclease , gene
— DNA‐dependent RNA polymerase activities were solubilized from the brain nuclei of young rats. Six forms of RNA polymerases were distinguished on DEAE‐Sephadex A‐25 chromatography and designated A, BI, BII, CI, CII, and Oil by their sensitivities to α‐amanitin. CII enzyme was shown to derive from CIII enzyme by serine‐protease digestion. CI enzyme was also suggested to be a product of a proteolytic process. Using a DNA template, enzyme A was completely resistant to α‐amanitin; BI and BII enzymes were equally sensitive to this toxin (50% inhibition at 0.006 μg/ml); while C enzymes showed intermediate sensitivity (50% inhibition at 30 μg/ml). When poly[d(A‐T)] was used as a template, α‐amanitin sensitivities were altered in A, CI, CII, and CIII enzymes without any change in the BII enzyme. CI, CII and CIII enzymes were greatly stimulated by poly[d(A‐T)], whereas A and BII enzymes were only slightly stimulated. All six forms of RNA polymerases were extensively characterized with respect to their ammonium sulphate optima, effects of divalent metal ions, template requirements and pH optima, using DNA and poly[d(A‐T)] as templates. The results show new findings in several properties and supply basic data for discussion and future studies on RNA metabolism of the brain.