Figure 5

Left: pH dependence of transformed Gibbs free energy of reaction for biotic and abiotic NCA formation equilibria from aspartate and carbamate (a), urea (b), cyanate (c), carbamoyl phosphate (d), and biuret (e). The values are calculated for pMg = 5, ionic strength = 1 M. Right: the corresponding reactions, conventionally written with all reagents in the fully protonated form.