摘要
重组水蛭素ＨＶ２是凝血酶的特异性抑制剂，是一种非常稳定的蛋白质。温度的升高（１００℃水浴）和ｐＨ（１─１３）的改变不影响其活力，在某些变性剂（８ｍｏｌ／Ｌ尿素、１％ＳＤＳ和６ｍｏｌ／Ｌ盐酸胍）存在的条件下也非常稳定，０．１ｍｏｌ／Ｌ的ＤＴＴ在７０℃时使其部分失活，只有ｐＨ和温度同时升高其活力才开始下降，ｐＨ１３、８０℃处理１５ｍｉｎ即完全失活，氨基酸组成和活性分析发现失活样品的Ｃｙｓ和Ｌｙｓ被破坏。重组水蛭素ＨＶ２含有一个结构紧密的Ｎ端核心区和一个无序的Ｃ端尾部。其Ｎ端的３个Ｌｙｓ－Ｘａａ键均不被胰蛋白酶水解；胃蛋白酶及糜蛋白酶消化后，分离所得片段，氨基酸组成分析发现Ｎ端核心区依然保持很高的抗凝血酶活性，继续消化２４ｈ，核心区不被进一步降解。
Recombinant hirudin HV2 is a remarkable protein. It is stable under extreme pH(1─13),high temperature (100℃),and in the presence of some denaturants (8M urea,1% SDS and 6M guanidinium chloride). In 0. 1M DTT at 70℃ and at PH1 for 24h,hirudin is partially inactivated. One condition which rapidly inactivates hirudin is the combined effect of elevated temperature and high PH. Amino acid composition analysis indicates the decrease of cysteine and lysine in inactivation. Hirudin comprises a compact amino-terminal domain and a disorderly acidic carboxyl-terminal tail. All three Lys-Xaa bonds are resistant to trypsin. Digestions with pepsin and chymotrypsin,hirudin is cleavaged into some fragments. Amino acid composition and anti-amidolytic analysis showed amino-terminal core fragment still has high anticoagulant activity. The thrombin inhibitory activity of hirudin remains highly even after 24h incubation with these proteases
关键词
重组水蛭素
稳定性
水蛭素
rHirudin
Stability
Denaturant
Proteases
