Qβ Replicase-associated, Polycytidylic Acid-dependent Polyguanylic Acid Polymerase

I. Characterization of the Reaction

抄録

The general properties of Qβ replicase-associated, polycytidylic acid-dependent polyguanylic acid polymerase (poly (G) polymerase) have been investigated. The results indicated that the poly (G) polymerase reaction was distinct from the Qβ replicase reaction by several different criteria: (1) Optimum temperature of the poly (G) polymerase reaction was 28-32°C, whereas that of the Qβ replicase reaction was 32-35°C. (2) Mn²⁺ could entirely substitute for Mg²⁺ in the poly (G) polymerase reaction, but could not do so in the Qβ replicase reaction. (3) The K_m for GTP of the poly (G) polymerase was 2×lO^-5_M, which was about one-tenth of that for GTP of the Qβ replicase. (4) The poly (G) polymerase catalyzed the synthesis of poly (G) by transcribing poly (C), but did not catalyze the further reaction: synthesis of poly (C) from poly (G).