– Trypsin is a serine protease that can be isolated from fish to hydrolyze lysine or arginine carboxy-side proteins. With the anti-inflammatory activity, Trypsin could induce the cell membrane fusion of PDCoV-infected cells through the interaction between the S glycoprotein of PDCoV and pAPN, activate PAR2 and PAR4, and promote cell proliferation and differentiation. Trypsin can be used to promote wound healing and study neurogenic inflammation.