Band centrifugation of macromolecules in self‐generating density gradients. II. Sedimentation and diffusion of macromolecules in bands

Abstract

Abstract Three approaches to the simultaneous sedimentation and diffusion of hands or zones of noninteracting homogeneous macromolecules are examined: ( 1 ) The authors' method of moments: ( 2 ) the transport me of Sehumaker and Rosenbloom; and ( 3 ) the stochastic solution of the Lamm equation due to Gehatia and Katehalski. All three methods indicate that the motion of the maximum of the hand may be used to evaluate the sedimentation coefficient. The moment, method provides relations which appear to be useful for measuring diffusion coefficients. Relations are given for the analysis of resolved components. The problem of measuring sedimentation coefficients of macromolecules with concentration‐dependent sedimentation coefficients is examined. Methods are described for evaluating the sedimentation coefficient in these systems and for obtaining the sedimentation coefficient at infinite dilution. Methods are described for determining the weight‐average sedimentation coefficient in Multi‐component systems, and the differential and integral distribution of sedimentation coefficients of macromolecules with low‐diffusion coefficients.