Fig. 7.
Temperature and pH dependence of β-haematin formation at the lipid-water interface. The Arrhenius plot (a) was constructed from rate constants (k) measured in an MSG interface system at pH 4.8 and temperatures ranging between 25 and 50 °C. The slope gives an activation energy of 76 ± 16 kJ/mol. The effect of pH (b) was measured at 37 °C and using an MSG interface system. The solid line fitted through the pH data is a best fit to an equation representing two pKa values with, pKa1 = 2.3 ± 0.01 and pKa2 = 5.2 ± 0.01.