Kex2 is a Ca2+ dependent serine protease and cleaves at C-terminal site of Lys-Arg, Arg-Arg, Pro-Arg in pro-α-factor and killer-toxin precursors maturing.But Kex2 can’t recognize and cut a single basic amino acid,such as carboxyl end peptide bond of arginine and lysine. Recombinant Kex2 protease is a genetically engineered protein expressed in Pichia pastoris and with equivalent properties compared to native Saccharomyces cerevisiae Kex2. The activity of Kex2 is not affected by the conventional serine protease inhibitors such as PMSF,TPCK,TLCK inhibition.The optimal pH of Kex2 protease is 9.0. It is stable in buffer (pH 5.0-6.0).