DIFFERENCE IN THE MECHANISMS OF POLY(DT) SYNTHESIS BY DNA POLYMERASE-BETA AND POLYMERASE-GAMMA

Poly(dT) products which were synthesized depending on (rA)n·(dT)12-18 as a template primer by mammalian DNA polymerases βand γ were analyzed by alkaline sucrose gradient centrifugation. The size of the population of poly(dT) chains synthesized by DNA polymerase β increased slowly and consistently during incubation up to at least 30 min. On the other hand, the product size with DNA polymerase γ reached the final size (7 s) within 5 mm and the number of products increased during further incubation. Comparison of product number per enzyme molecule suggests that DNA polymerase β acts on multiple primers in a distributive fashion while DNA polymerase γ completes poly(dT) chains of large size in a one-by-one fashion. © 1979 By The Journal Of Biochemistry.