pK(a) values and redox potentials of proteins. What do they mean?
In this article, we review a microstate model that uses protonation and redox microstates in order to understand the complex pH and redox titration of proteins and other polyelectrolytes. From this model, it becomes obvious that it is impossible to assign pK(a) values or redox potentials to individual protonatable or redox-active sites in a protein in which many of such sites interact. Instead each site is associated with many microscopic equilibrium constants that may lead to irregular or even non-monotonic titration curves of some groups. The microstate model provides a closed theoretical framework to discuss such phenomena.
Structural Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse 30, BGI, 95447 Bayreuth, Germany. ullmann@uni-bayreuth.de
G Matthias
GM
Ullmann
Elisa
E
Bombarda
D000596:Amino Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics
D000596:Amino Acids; D011506:Proteins