牛初乳免疫球蛋白体外胰蛋白酶消化研究

In vitro digestion of bovine IgG by trypsin

采用硫酸铵盐析、DEAE离子交换层析纯化牛初乳免疫球蛋白IgG,并对其进行胰蛋白酶体外消化研究.结果表明:牛IgG比牛血清白蛋白(BSA)抗胰蛋白酶水解.IgG经低温巴氏灭菌处理后,其被胰蛋白酶消化的能力变化不大;经90℃高温3min处理后,被胰蛋白酶水解率大幅度提高,提示IgG的立体结构在保护其完整性方面有重要作用;另外,藏绵羊小肠液对IgG的降解率高于胰蛋白酶.

Immunoglobulin G is purified by salting out, gel chromatography, and DEAE ion exchange chromatography from bovine colostrum and hydrolyzed by trypsin in vitro. IgG is more difficult to digest by trypsin in vitro than bovine serum albumin. Paterization of IgG has no significant effect on digestion of IgG by trypsin. Treatment of IgG at 90℃ for 3min significantly increases the digestibility of IgG by trypsin in vitro, suggesting that the conformation of IgG is crucial in protecting its integrity. The in vitro digestibility of IgG by small intestine fluid from Tibetan sheep is higher than that of trypsin.