重组刺桐胰蛋白酶抑制剂的复性纯化

刺桐胰蛋白酶抑制剂（ETI）是一种丝氨酸蛋白酶抑制剂，可抑制胰蛋白酶、胰凝乳蛋白酶及组织纤溶酶原激活剂（t-PA）等。本研究利用大肠杆菌高密度发酵表达ETI，产物以包涵体形式存在，经体外以脉冲稀释的方式复性并纯化后，每升发酵液可得ETI 1000mg以上，纯度大于95％，比活为1．55IU／mg。ETI制成的ETI-Sepharose亲和胶，每ml可吸附重组瑞特普酶融合蛋白（Trx-rPA）2mg，可应用于制备t-PA及其衍生物如r-PA等药用蛋白。

Refolding and Purification of Erythrina Trypsin Inhibitor

Erythrina trypsin inhibitor (ETI) is a natural serine protease inhibitor, with high inhibitive activity to trypsin, chemotrypsin and tissue-type plasminogen activator (t-PA). In this work, ETI was over expressed as inclusion bodies in high density fermentation of E. coli. By means of pulse refolding and two-step purification, over 1000 mg of ETI was obtained from one litre of culture. Its purity was over 95% , and specific activity 1.55 IU/mg. ETI, immobilized on Sepharose with high binding capacity of the recombinant fusion protein Trx-rPA up to 2 mg/ml gel, is a promising choice for purifying t-PA and its derivatives such as r-PA .