Allowance for effects of thermodynamic nonideality in sedimentation equilibrium distributions reflecting protein dimerization.
This reexamination of a high-speed sedimentation equilibrium distribution for α-chymotrypsin under slightly acidic conditions (pH 4.1, I(M) 0.05) has provided experimental support for the adequacy of nearest-neighbor considerations in the allowance for effects of thermodynamic nonideality in the characterization of protein self-association over a moderate concentration range (up to 8 mg/mL). A widely held but previously untested notion about allowance for thermodynamic nonideality effects is thereby verified experimentally. However, it has also been shown that a greater obstacle to better characterization of protein self-association is likely to be the lack of a reliable estimate of monomer net charge, a parameter that has a far more profound effect on the magnitude of the measured equilibrium constant than any deficiency in current procedures for incorporating the effects of thermodynamic nonideality into the analysis of sedimentation equilibrium distributions reflecting reversible protein self-association.
Peter R
PR
Wills
David J
DJ
Scott
Donald J
DJ
Winzor
D000143:Acids / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002918:Chymotrypsin / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D046912:Multiprotein Complexes / Q000737:chemistry; D055503:Protein Multimerization; D055672:Static Electricity; D013816:Thermodynamics
D000143:Acids; D046912:Multiprotein Complexes; D002918:Chymotrypsin; C117608:alpha-chymotrypsin