肠三叶因子的纯化、理化性质及其稳定性分析  

Purification,physical properties and stability of intestinal trefoil factor

作　　者：孙勇[1] 张勇[2] 吕尚军[2] 吴炜[2] 汪仕良[2] 彭曦[2] 

机构地区：[1]解放军第97医院烧伤整形科,江苏徐州221004 [2]第三军医大学西南医院全军烧伤研究所,创伤,烧伤与复合伤国家重点实验室,重庆400038

出　　处：《第四军医大学学报》2009年第6期497-500,共4页Journal of the Fourth Military Medical University

基　　金：国家自然科学基金(30200294)

摘　　要：目的:制备高纯度的肠三叶因子(ITF),研究其理化性质及其在模拟胃肠道环境中的稳定性.方法:首先利用硫酸氨分级沉淀、镍离子亲和层析、超滤离心三步法纯化ITF,然后分析氨基酸序列、肽指纹图谱、三级结构,最后建立模拟胃肠道环境模型,研究ITF的稳定性.结果:经过三步纯化后ITF的纯度超过95%,产量约为50mg/L;氨基酸序列分析、肽指纹图谱分析与预测值完全一致,质谱分析显示精确Mr约为7879.4,与理论值(7679.7)基本一致;三级结构研究证实ITF主要以二聚体的形式存在;模拟胃肠道环境中的稳定性研究显示,ITF在蛋白酶/ITF的比例高达1∶1时,经过4h消化,ITF二聚体残余量超过50%;在pH值2.0～12.0的缓冲液中,37℃水浴5h后,残余量均超过90%;pH7.8缓冲液37℃水浴5d,残余量超过70%.结论:获得了高产量、高纯度及高度稳定的ITF,为ITF大规模的工业化生产及口服药的制备打下了坚实的基础.AIM： To obtain intestinal trefoil factor （ITF） with high purity, to explore the physical properties of purified ITF and to assay the stability in an in vitro simulated gastrointestinal environment. METHODS： ITF was isolated from the Pichia pastoris culture supernatant by ammonium sulfate precipitation, Ni-NTA affinity chromatography and uhrafiltration. Mass spectrometry analysis, N-terminal amino acid sequence analysis, peptide mass fingerprint analysis and non-reducing Tricine SDS-PAGE analysis were performed. An in vitro restitution model was to be established and the stability in simulated gastrointestinal environment to be determined. RESULTS： The yield of ITF was about 50 mg/ L, with the purity after purification above 95%. The N-terminal sequence of ITF was shown to be consistent with the sequences we designed. Mass spectrometry analysis demonstrated that the molecular weight of ITF was 7879.4, approximately the same as the calculated value, 7 679.7. Native ITF existed mainly in dimer form. ITF was robustly resistant to trypsin and pepsin, and even at a high enzyme/substrate （w/w） ratio of 1/1, more than half of ITF existed in dimer form. Different pH values ranging from 2.0 to 12.0 had little effect on the dimer of ITF and residual dimer was greater than 90%. After water bath at 37℃ for 5 d, more than 70% of ITF was not hydrolyzed. CONCLUSION ： We have produced soluble ITF with a high yield and high purity and with resistance to proteases, heat, acid and alkali. The results lay a foundation for the commercial production of ITF and provides theoretical evidence for the oral use of ITF.

关 键 词：肠三叶因子 纯化 药物稳定性 

分 类 号：Q786[生物学—分子生物学]