Figge J. Role of Non-Volatile Weak Acids (Albumin, Phosphate and Citrate). In Stewart's
Textbook of Acid-Base. Kellum JA and Elbers PWG, editors. Amsterdam: AcidBase.org. 2009.
Chapter 11, pages 217 - 232.
Predicted titration curve of human serum albumin at 37 oC and ionic strength of
approximately 0.15 over the pH range 5.0 to 9.0, as calculated by the Figge-Fencl model
(smooth curve). Predicted charge displayed by albumin is given in Eq / mol albumin. The
predicted isoelectric point is at pH = 5.48. The independent experimental data points of
Fogh-Andersen, Bjerrum and Siggaard-Andersen [from Figure 4 in reference 9] are also shown
(diamonds). These experimental data points give the intrinsic charge carried by human albumin
at 37 oC in the presence of physiologic concentrations of NaCl, KCl, and CaCl2. Note
the close agreement between the titration curve predicted by the Figge-Fencl model and the
independent experimental data points of Fogh-Andersen and colleagues.