Determination of ionization
state of titratable residues for simulations.
(a) Chemical structures of titratable residues (ASP, GLU, HIS, LYS,
ARG) and the resulting ionized structure at pH 3.5. Red and blue color
denotes negatively and positively charged residues, respectively.
(b) Localization of ionized residues on albumin at pH 7.4 and pH 3.5.
Inset shows the total charge per residue type and for the protein
overall at the two pH values. At pH 7.4, the protein has a total charge
of −9, while at pH 3.5 the charge is +100 (including the amine
terminal group).