Figure 7

Metastabilities of proteins around a pseudoinvariant point. Activities of CO_2(aq), NH_3(aq), H₂S_(aq) and H₂O were calculated using a buffer consisting of the proteins from the METXX organisms listed in Table 1. The variables set in the buffer calculation were activities of proteins equal to 10^-3, T = 100°C, P = 1000 bar, log $f_{{\text{O}}_{2(g)}}$ = -58 and pH 7. The diagrams show the variation of protein metastability as a function of (a) temperature and pressure and (b) log $f_{{\text{O}}_{2(g)}}$ and pH. The dashed line in (b) represents the lower stability limit of H₂O at this temperature and pressure.