中文摘要：

[目的]克隆决明胰蛋白酶抑制剂全长cDNA序列,并构建原核表达载体。[方法]从决明种子中提取胰蛋白酶抑制剂总RNA,通过RT-PCR得到胰蛋白酶抑制剂cDNA,纯化后与PMD19-T载体连接,转化至大肠杆菌DH5α,获得了决明胰蛋白酶抑制剂基因的全长序列,并将该序列克隆到原核表达载体pET-28a（＋）中,构建重组质粒pET-28a（＋）/COTI。[结果]决明胰蛋白酶抑制剂基因核苷酸长度为630bp,编码一条长度为209个氨基酸的多肽。决明胰蛋白酶抑制剂与不同植物来源的Kunitz蛋白酶抑制剂有高度的同源性,表明其属于Kunitz蛋白酶抑制剂家族成员。所获重组质粒pET-28a（＋）/COTI经过双酶切鉴定,其含有目的片段,且重组质粒构建正确。[结论]克隆了决明胰蛋白酶抑制剂的全长cDNA序列,并成功构建了含有该基因的原核表达载体,这为该基因的进一步表达及功能鉴定奠定了基础。

英文摘要：

[ Objective]To clone the full length of Cassia obtasifolia trypsin inhibitor gene cDNA and construct the prokaryotic expression vector. [Methods]The total RNA of Cassia obtasifolia trypsin inhibitor was extracted from seed of Cassia obmsifolia and its cDNA was obtained by RT - PCR. The purified RT - PCR products and pMD19 - T vector were ligated and transformed into host strain E. coli DH5α. The aim gene was expressed on the prokaryotic expression vector pET - 28a（ ＋ ） and a recombinant plasmid pET- 28a（ ＋ ）/Cassia obtusifolia trypsin inhibitor was constructed successfully. [ Results] The full length of Cassia ob- tusifolia trypsin inhibitor gene was composed of 630 bp, which encodes 209 amino acids. Cassia obtusifolia trypsin inhibitor has high homology with Kunitz protease inhibitor from different plants,which indicates that it belongs to the family of Kunitz protease inhibitor. [ Conclusion] The full length of Cassia obtusifolia trypsin inhibitor gene cDNA was cloned and prokaryotic expression vector was constructed successfully,whieh laid the foundation for the further expression and function identification of this gene.