title: Substrate, metal and template effects on inhibition of bacteriophage-qbeta ribonucleic acid polymerase by ortho- and pyro-phosphate.
abstract: Two reactions of bacteriophage-Qbeta RNA polymerase with synthetic templates were characterized and used to study the effects of substrate, metal and template on inhibition by Pi and PPi. Analysis of the poly(C)-dependent reaction yielded results on kinetics, GTP-dependence, preference for Mn2+ over Mg2+, and Michaelis constants for template similar to those in the literature. New data are provided for the poly(U2,C)-dependent reaction. Our results suggest that GTP and Mn2+ can form relatively stable complexes with the polymerase and that such complexes change the interaction of the enzyme with the inhibitors, Pi and PPi.
mesh_terms: D003090:Coliphages / Q000201:enzymology*; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors*; D011756:Diphosphates / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology*; D011066:Poly C / Q000378:metabolism; D011072:Poly U / Q000378:metabolism; D013698:Templates, Genetic
chemical_list: D011756:Diphosphates; D010710:Phosphates; D011072:Poly U; D011066:Poly C; D008345:Manganese; D006160:Guanosine Triphosphate; D012321:DNA-Directed RNA Polymerases; D008274:Magnesium