Isoelectric Fractionation, Analysis, and Characterization of Ampholytes in Natural pH Gradients. IV. Further Studies on the Resolving Power in Connection with Separation of Myoglobins.

Publisher Website
Google Scholar
Abstract
The resolving power of the method of stationary electrolysis for isoelectric focusing of proteins is studied on a system of myoglobins, which is found to contain 2 components with a difference in isoelectric point (pI) of only 0.06 pH units. With the aid of a new system of carrier ampholytes, these components are found to be completely resolvable, and their zone breadths satisfy a theoretically derived equation. Further, by introduction of an exact definition of a resolving power, a mathematical equation for the latter is derived. It shows that the resolving power improves with the shallowness of the pH course and with the field strength, for both variables with a square root dependence. There is no theoretical limit to the resolving power. With the present apparatus and technique, a resolving power of 0.02 pH units is calculated for proteins physico-chemically similar to myo-globin. With some technical improvement, a resolving power of 0.01 pH unit should be possible. Thus, if 2 proteins have a pI difference big enough to be picked up by a pH meter of standard accuracy, the proteins can be resolved by stationary electrolysis.