Figure 3

MS analysis of the PE reaction mixtures with Taq polymerase at 72 °C. PE was performed with a mixture of dATP, dGTP, dCTP, and Y for varying amounts of time (10, 30, and 60 min). The concentration of the nucleotides was 200 μM (each). The peaks were assigned based on their m/z values as follows: (1) M; (2) M + dA; (3) M-dT + Y; (4) M + Y, M-dT + Y + dA and M-dT + Y + dG; (5) M-dT + Y + Y; (6) F; and (7) F + Y. Taq polymerase generates a diverse pool of products because of the enzyme transferase activity and nucleotide exchange via pyrophosphorolysis.