Soybean inhibitors: II. Preparative electrophoretic purification of soybean proteinase inhibitors on polyacrylamide gel

A preparative electrophoretic procedure is described for purifying commercial preparations of two distinct soybean proteinase inhibitors on polyacrylamide gel. One inhibitor, soybean trypsin inhibitor of Kunitz, is obtained in a highly pure state starting with a crude, commercial sample. The other, prepared according to Birk et al. (6), is freed of several minor contaminants. In addition to the high purity of samples obtained with the technique, other advantages include simplicity as a one-step operation, and applicability of the method to a continuous batch operation on a 24 hour cycle.