Modification of pH gradients in isolelectric focusing by the pH of the anolyte

In isoelectric focusing on polyacrylamide gel, pH gradients exhibited a systematic shift along the pH‐axis in proportion to the pH of the anolyte. Thus, more acidic anolytes produced more acidic pH gradients, and more basic ones gave rise to more basic pH gradients. In all cases the pH's of the anolyte and catholyte were kept outside the pI‐range of the carrier ampholytes used. Increasing the pH of the anolyte stabilized pH gradients, while the pH of the catholyte, within the range tested, had no systematic effect on pH gradient stabilization. From a practical viewpoint, modification of pH gradients by the anolyte provides increased flexibility in pH gradient design for electrofocusing. From a theoretical viewpoint, the selective anolyte effect on pH gradients in isoelectric focusing on polyacrylamide gels supports the hypothesis previously advanced by Murel et al., which relates pH gradient decay in electrofocusing to progressive protonation from the anodic pH gradient terminus.