Apparent temperature and pH optima of Danio rerio pol β. Effect of temperature (A) and pH (B) on the pol β activities of D. rerio(closed lozenge) and rat (open circle). The activities of pol β were determined by the incorporation dTTPs under standard assay conditions. (A) Effect of pH on pol β activity was carried out at various pHs from 7.0-10.5. Incubation was carried out at 30°C (Danio rerio) or 37°C (rat) for 5 min. (B) Effect of temperature on pol β activity was carried out at various temperatures: 15-42°C (Danio rerio) or 15-50°C (rat).