Reductive alkylation of surface amino groups in high activity PPK ( pig pancreas kallikrein) by glyoxylic acid in the presence of sodium cyanoborohydride results in increasing the stability against irreversible thermoinactivation. 以自制高活性PPK为材料,在氰基硼氢化钠存在下经水溶性乙醛酸修饰其表面氨基,使其抗不可逆热失活稳定性有显著提高。