title: The role of subunits in yeast DNA-dependent ribonucleic acid polymerase A.
abstract: The properties of RNA polymerase A, which lacked the subunits of 48 000, 37 000 and 16 000 mol. wt., were compared with those of RNA polymerase A by using native calf thymus DNA as the template. The results showed that: (1) the specific activity of RNA polymerase A was about one-third that of RNA polymerase A; (2) more than 80% of RNA polymerase A, but only about 25% of RNA polymerase A, made RNA; (3) initiation by RNA polymerase A, but not by RNA polymerase A, began after a lag of 2 min; (4) the temperature-dependence for productive binding to DNA was greater for RNA polymerase A; (5) the apparent Km for UTP was greater for RNA polymerase A. These results support the supposition that the subunits missing from RNA polymerase A are involved in DNA binding [Huet, Dezélée, Iborra, Buhler, Sentenac & Fromageot (1976) Biochimie 58, 71-80] and show also that the loss of these subunits affects the elongation reaction.
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology; D055598:Chemical Phenomena; D002621:Chemistry; D004247:DNA / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D012313:RNA / Q000096:biosynthesis; D012318:RNA Polymerase I / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013329:Structure-Activity Relationship; D014544:Uridine Triphosphate / Q000494:pharmacology
chemical_list: D012313:RNA; D006160:Guanosine Triphosphate; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D000645:Ammonium Sulfate; D014544:Uridine Triphosphate