Figure 8.

Characterization of Tt72 pol activity optima. Enzyme activity was estimated by measuring the incorporation of radiolabeled nucleotide [³H]-dTTP into activated calf thymus DNA at 55 °C; identical aliquots of Tt72 pol were assayed in three independent sample replicates for each experiment. The variable factors were (a) temperature (25–80 °C), (b) heating time at 55 °C (0–4 h), (c) incubation for 10 min at 55–95 °C, and (d) heat shock for 10 min at 75 °C in the presence of compatible solutes, such as proline, trehalose, betaine, ectoine, and TMAO at a concentration of 0.5 M. (e) pH range (6.5–10.5), (f) MgCl₂ concentration (0–2.5 mM), (g) KCl concentration (0–150 mM), and (h) (NH₄)₂SO₄ concentration (0–80 mM). Y-axis shows the percent of polymerase activity to maximal activity. Error bars represent SD from the mean.