Isoelectric points of Kunitz' crystalline soybean trypsin inhibitor (STl), Bowman-Birk STI, and STI prepared by chromatography on diethylaminoethyI (DEAE)-cellulose were investigated by isoelectric focusing, gel filtration, ion-exchange resin treatment, solubility test, and titration. Results suggest that the STI of Kunitz may have an isoelectric point below pH 4.5. The isoelectric focusing pat...
