Fig 1.

Effect of NaCl concentration (upper), pH (middle), and temperature (lower) on the hydrolytic activity of Lake Arreo enzymes. The heat map colors represent the relative percentages of specific activity (U/mg) compared to the maximum (100%) within each enzyme, using pNP butyrate as the substrate. The effect of NaCl concentration was measured in 20 mM HEPES buffer (pH 7.0) at 30°C and varied from 0 to 1.2 M; the pH dependence was tested in the range of pH 4.0 to 9.5 at 30°C in 20 mM buffers; the temperature dependence in the range of 4 to 70°C at pH 7.0 was also determined. Reaction conditions were as described in Table 1 and Materials and Methods.