Trypsin(Cocoonase) is a serine protease enzyme, and hydrolyzes proteins at the carboxyl side of the Lysine or Arginine. It activates PAR2 and PAR4 and induces cell-to-cell membrane fusion in PDCoV infection by the interaction of S glycoprotein of PDCoV and pAPN. It also promotes cell proliferation and differentiation and can be used in the research of wound healing and neurogenic inflammation.