SEDIMENTATION EQUILIBRIUM IN REACTING SYSTEMS .6. SOME APPLICATIONS TO INDEFINITE SELF-ASSOCIATIONS . STUDIES WITH BETA-LACTOGLOBULIN A

If it be assumed that all molar equilibrium constants are equal, then it is possible to analyze indefinite self-associations. The equations for the second positive moment ψ and the second negative moment Mt2Σ(Ci/Mi2) and its apparent value are developed here for indefinite self-associations. It is shown how these quantities may be used with other available quantities (C, [formula omitted], and M1/Mn app) in the analysis of indefinite self-associations. Some sedimentation equilibrium experiments on β-lactoglobulin A in 0.2 M acetate buffer at 16° and pH 4.6 are reported. It appears that an indefinite self-as sociation best describes the experimental data; the details of the analysis are reported. In addition attention has been called to some experimental details which we believe aided us in these experiments. In an appendix to this manuscript it has been shown how the second negative moment M12ψ(ci/Mi2) or its apparent value can be developed from sedimentation equilibrium or osmometry of self-associating systems. Besides extending the analysis of discrete selfassociations and being used for possible checks on the analysis, it can also be applied to indefinite selfassociations. © 1968, American Chemical Society. All rights reserved.