Isoelectric Focusing in Polyacrylamide Gel and its Application to Immunoglobulins

Abstract

THE principle of isoelectric fractionation was applied to the separation of amino-acids as early as 1912 by Ikeda and Suzuki (Japanese patent quoted in ref. 8), but the technique did not become practical for the fractionation of macromolecular ampholytes such as proteins until the introduction of natural pH gradients¹ and suitable carrier ampholytes^2–4. Svensson described an apparatus for isoelectric focusing in shallow pH gradients formed by low molecular weight ampholytes and stabilized by sucrose density gradients³. In this form the technique has been successfully applied to studies on the heterogeneity of myoglobins^4,5, cytochrome c⁶, lactoperoxidase⁷ and a number of other proteins (see review by Haglund⁸).