Accessory sex gland (ASG) secretory proteins of the Chinese mitten crab (Eriocheir sinensis) can effectively digest the spermatophore wall. In order to identify which proteins participate in spermatophore wall digestion, a 50-kDa protein secreted from the ASG was purified to homogeneity by a series of isolation steps, including ammonium sulfate fractionation, Sephadex G-25 S gel-filtration, ion...