Determination of anti-protease homogeneity

Virgin and modified [single peptide bond between arginine (63) and isoleucine (64) is cleaved] soybean anti-trypsin was separated by chromatofocusing using a narrow pH range. The separation on anion-exchange and reversed-phase chromatography was less satisfactory. Anti-proteases isolated by affinity chromatography from Boophilus decoloratus were monitored for the formation of any modified protein, with chromatofocusing.