title: Synthesis of dinucleoside tetraphosphates by RNA polymerase B (II) from calf thymus.
abstract: Highly purified RNA polymerase B (II) from calf thymus catalyses the synthesis of dinucleoside tetraphosphates from ribonucleoside triphosphates in the absence of an oligonucleotide primer or additional protein factors. The reaction requires a DNA template and bivalent cations such as Mn2+ or Mg2+. It is strongly inhibited by heparin and high concentrations of alpha-amanitin but not by rifampicin. On a given template various dinucleoside tetraphosphates of different sequence are formed although the yield depends on the nature of the template.
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D015226:Dinucleoside Phosphates; D006493:Heparin / Q000494:pharmacology; D009841:Oligonucleotides / Q000096:biosynthesis*; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012293:Rifampin / Q000494:pharmacology; D013379:Substrate Specificity; D013698:Templates, Genetic; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D000546:Amanitins; D015226:Dinucleoside Phosphates; D009841:Oligonucleotides; D006493:Heparin; D012319:RNA Polymerase II; D012293:Rifampin