Hydrophobic interaction chromatograms of four AEX fractions. A continuous gradient of ammonium sulfate (AS) concentration (30-0%) was used for eluting. (A) FI and (B) FII were eluted as single prominent peaks. (C) FIII was separated into three sub fractions with protease activity: FIII-1, FIII-2 and FIII-3. (D) FIV was fractionated into multiple peaks, however, only one fraction showed protease activity. All active fractions were indicated by arrows.