Fig. 3.

Effects of hydrostatic pressure on LDH activity in muscle homogenates from four fish species with different degrees of piezophilic adaptation. Different colors in the graph correspond to the results of independent experiments. Each individual dataset was scaled to represent the pressure dependence of the percent of the (extrapolated) maximal activity (see Materials and methods). Solid lines represent the results of fitting the combined dataset to Eq. 6. The values of $\mathrm{\Delta }{V}_{\text{PP}}^{{}^{\circ }}$ and P _½ and A ₀ obtained from these approximations are shown in Table 2. In the case of N. kermadecensis, where the activity of the enzyme exhibits a distinct increase in the interval of 1–1200 bar, the low‐ (1–1500 bar) and high‐pressure (1200–4800 bar) parts of the dataset were fitted separately. Here, the dashed line represents the fitting of the initial part of the dependence, which resulted in the estimates of A ₀ (46 ± 3%), A _max (52 ± 2%), P _½ (146 ± 97 bar) and $\mathrm{\Delta }{V}_{\text{PP}}^{{}^{\circ }}$ (−109 ± 60 mL·mol⁻¹).