The Physical Chemistry of Secalin. Electrophoresis and Diffusion Constant Studies of the Prolamine of Rye¹

The Investigation of Proteins by Diffusion Measurements.

“…It may be seen from table 1 that the maximum ordinate of the compound diffusion curve is always higher than that of the diffusion curve of component 1.…”

“…In the following, we shall merely review briefly the elementary principles of the diffusion process as it is most frequently met in actual experimentation. 1 Presented at the Symposium on Physicochemical Methods in Protein Chemistry, which was held under the joint auspices of the Division of Physical and Inorganic Chemistry and the Division of Biological Chemistry at the 102nd Meeting of the American Chemical Society, Atlantic City, New Jersey, September 8-12, 1941. We consider a system in which a solution of concentration Co is in contact with its solvent, as shown in the top section of figure 1. The boundary between solution and solvent is at the point x = 0, and positive values are assigned to x in the direction of increasing concentration.…”

“…The quantity 1--^-1 llOO gives the percentage change in the maximum ordinate of the diffusion curve of a mondisperse solution. In table 1 values are given for this quantity, calculated for various ratios of D2/Di in relation to assumed values of c2/ci. <r has been assumed to be equal to or, i.e., we compare the maximum ordinate of the diffusion curve of a monodisperse solution of the faster diffusing component with that of a solution containing both components in varying relative concentrations.…”

“…The influence of concentration on the diffusion rate may be studied by either one of the following methods: (1) the initial concentration difference is varied by increasing the concentration of the solution and keeping that of the solvent at zero; (2) the initial concentration difference is kept constant, but the absolute concentration of both solution and "solvent" is increased. The first method is limited in scope by the optical disturbances occurring with high refractive-index gradients, as discussed in section D2 (page 22).…”