蛋白折叠液相色谱法复性和纯化大肠杆菌表达的重组人粒细胞集落刺激因子

用蛋白折叠液相色谱法(PFLC)对大肠杆菌表达的包涵体形式的重组人粒细胞集落刺激因子(rhG-CSF)进行了复性并同时纯化。用Cu2+-亚氨基二乙酸（IDA） Sepharose作为固定化金属离子亲和色谱的固定相。在低浓度脲存在下,以咪唑为洗脱剂,采用线性梯度洗脱rhG-CSF。该法仅通过一步PFLC分离,减少了复性过程中rhG-CSF的聚集,复性后的rhG-CSF的比活性为1.8×108 IU/mg,纯度为97%,质量回收率为32%。     

重组人干扰素-γ的制备与鉴定

用聚乙二醇200疏水相互作用色谱固定相(PEG200-STHIC)分别在色谱柱和色谱饼上完成了一步复性并同时纯化来源于大肠杆菌(E.coli)表达的重组人干扰素-γ(rhIFN-γ)。为了能使色谱分离方法用于不同来源的rhIFN-γ的纯化,对rhIFN-γ在反相色谱、离子交换色谱、固定化镍离子亲和色谱上的保留行为也进行了研究。色谱柱纯化的rhIFN-γ收集液经排阻色谱除盐和冷冻干燥得到rhIFN-γ干粉。用基质辅助激光解吸电离飞行时间质谱对rhIFN-γ干粉进行了测定,rhIFN-γ单体的相对分子质量为17184.0,二聚体的相对分子质量为34204.4。用细胞病变抑制法(CPEI)测定rhIFN-γ干粉的比活性为9.5×108 IU/mg。用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）测定rhIFN-γ干粉的纯度高于95%。用色谱柱复性并同时纯化rhIFN-γ的质量回收率达到93.7%,纯度高于95%,比活性为4.3×107 IU/mg。结果表明,采用PEG200-STHIC色谱柱复性并同时纯化rhIFN-γ是一种十分高效的方法。     

γ-干扰素在反相高效液相色谱柱上色谱行为与分离的研究

用高效液相色谱法对基因工程下游包涵体所含目标蛋白进行分离纯化,较系统地研究了γ－干扰素在反相柱上的色谱行为及其影响因素。结果表明,复性后γ－干扰素伴有错配聚合体产生,其保留行为及洗脱谱图随构象不同而改变。分离系统的疏水性和粘度是影响γ－干扰素在固定相与流动相间传质扩散的重要因素。     

用疏水色谱复性并同时纯化蛋白质的机理及其应用

变性蛋白表面的疏水氨基酸残基有与疏水色谱固定相(STHIC)颗粒相互作用的倾向, 两者之间的疏水相互作用能够抑制变性蛋白分子间的相互聚集. 同时疏水色谱固定相还能在分子水平上给变性蛋白分子提供足够高的能量, 使其瞬时脱水并折叠成其天然构象或不同的折叠中间体. 变性蛋白在疏水界面上的折叠不仅取决于其氨基酸之间的特异性相互作用及疏水色谱固定相的结构, 而且还取决于固定相和流动相之间的协同作用. 同时, 还提出了高效疏水相互色谱(HPHIC)进行蛋白折叠的机理及其进行蛋白折叠时能实现质量控制的原理. 在适当的色谱条件下, HPHIC 可使几种变性蛋白一步实现复性及同时纯化. 此外, 还设计制造出了直径比柱长大得多的实验室型和制备型“变性蛋白复性及同时纯化装置, USRPP”, 该“装置”具有完全除去变性剂、使蛋白质复性, 与杂蛋白分离及易于回收变性剂的“一石四鸟”功能. 该“装置”对变性蛋白的复性和纯化效率与通常使用的长柱相当. 在制备规模情况下, 该“装置”可以在低压梯度条件下简便、快速、而经济地应用于重组蛋白药物的制备. 文中以重组人干扰素-γ为例, 说明了制备型“装置”在其复性及同时纯化生产工艺中的应用.     

高效离子交换液相色谱法分离绿脓杆菌外膜蛋白

利用高效ＤＥＡＥ离子交换液相色谱法分离纯化了绿脓杆菌标准菌株ＰＡＯ１外膜蛋白。流动相为ｐＨ８．０Ｔｒｉｓ－ＨＣｌ缓冲液,色谱柱为ＴＳＫｇｅｌ－ＤＥＡＥ－５ＰＷ（０．７５ｃｍ×７．５ｃｍｉ．ｄ．）。通过纯化外膜蛋白,可以为研究绿脓杆菌外膜通透性与抗生素耐药性之间的关系及缩短研究周期提供有效的方法。     

高效疏水相互作用色谱法复性与同时纯化重组人Flt3配体的包涵体蛋白质

Flt3配体(FL)是一类具有促进早期造血功能的细胞因子,在促进造血细胞生长发育及造血动员方面具有重要的临床应用价值。为了用基因工程方法获得大量用于临床和研究的重组人FL(rhFL)蛋白质,本文对在大肠杆菌(E. coli)中表达得到的Flt3配体的包涵体进行回收、洗涤,溶解于8 mol/L脲后在高效疏水相互作用色谱(HPHIC)柱上进行rhFL包涵体的复性与同时纯化,并对其保留特征和复性规律进行了研究。结果表明,在连续进样、变性蛋白质质量浓度为8.51 g/L、固定相选用端基为PEG800、流动相添加4 mol/L脲、1.8 mmol/L 还原型谷胱甘肽(GSH)和0.3 mmol/L氧化型谷胱甘肽(GSSH)、pH 7.0的优化条件下,复性与同时纯化rhFL包涵体的质量回收率为36.9%,纯度达94.5%以上。本文仅用一步HPHIC法成功地复性与同时纯化了rhFL蛋白质,为获得高活性的rhFL产品奠定了一定的工作基础。     

蛋白质制备色谱的研究

研究了蛋白质纯化制备的二种运行模式,其一,在色谱柱超载下纯化制备蛋白质模式,并成功地用离子交换色谱纯化制备了大豆中的胰蛋白酶,用反相液相色谱纯化了细胞色素Ｃ;其二,用溶质－溶质顶替色谱纯化制备了核糖核酸酶－Ａ,并对顶替色谱过程中诸参数进行了讨论和选择。     

高效离子交换液相色谱法分离绿脓杆菌外膜蛋白

 利用高效ＤＥＡＥ离子交换液相色谱法分离纯化了绿脓杆菌标准菌株ＰＡＯ１外膜蛋白。流动相为ｐＨ８．０Ｔｒｉｓ－ＨＣｌ缓冲液,色谱柱为ＴＳＫｇｅｌ－ＤＥＡＥ－５ＰＷ（０．７５ｃｍ×７．５ｃｍｉ．ｄ．）。通过纯化外膜蛋白,可以为研究绿脓杆菌外膜通透性与抗生素耐药性之间的关系及缩短研究周期提供有效的方法。     

疏水作用色谱法同时纯化及复性基因重组人干扰素-α

 使用高效疏水作用色谱直接从大肠杆菌表达的基因重组人干扰素 α(rhIFN α)包涵体的裂解液中纯化了rhIFN α ,并在纯化的同时获得了高的复性效率 ,使复性和纯化一步完成 ,大大地简化了操作步骤。用凝胶排阻色谱对该法纯化的rhIFN α进行了纯度测定 ,纯度达到 95 %以上。该法的活性回收率分别比稀释法和透析法高 1 0倍和 1 6倍。     

重组人细胞红蛋白的表达纯化及谱学表征

以可溶性和包涵体两种形式表达纯化得到了重组人细胞红蛋白, 并比较了其谱学特征和热稳定性. 可溶性蛋白经硫酸铵分级沉淀, 再依次经Hiprep 16/10 Q FF阴离子交换柱、Hiload16/60 Superdex 75 凝胶过滤柱和 CM Sepharose FF 阳离子交换柱纯化, 得到电泳纯的包涵体蛋白; 包涵体蛋白经盐酸胍变性溶解、外加血红素重组和柱层析得到了电泳纯的可溶性蛋白. 电喷雾质谱表明, 以这两种形式得到的蛋白分子量相差153.0, 紫外-可见吸收光谱、荧光光谱和圆二色光谱均表明, 这两种形式的蛋白在血红素构象上存在差异, 其热稳定性也不相同.     

Refolding and simultaneous purification of recombinant human proinsulin from inclusion bodies on protein‐folding liquid‐chromatography columns

Protein‐folding liquid chromatography (PFLC) is an effective and scalable method for protein renaturation with simultaneous purification. However, it has been a challenge to fully refold inclusion bodies in a PFLC column. In this work, refolding with simultaneous purification of recombinant human proinsulin (rhPI) from inclusion bodies from Escherichia coli were investigated using the surface of stationary phases in immobilized metal ion affinity chromatography (IMAC) and high‐performance size‐exclusion chromatography (HPSEC). The results indicated that both the ligand structure on the surface of the stationary phase and the composition of the mobile phase (elution buffer) influenced refolding of rhPI. Under optimized chromatographic conditions, the mass recoveries of IMAC column and HPSEC column were 77.8 and 56.8% with purifies of 97.6 and 93.7%, respectively. These results also indicated that the IMAC column fails to refold rhPI, and the HPSEC column enables efficient refolding of rhPI with a low‐urea gradient‐elution method. The refolded rhPI was characterized by circular dichroism spectroscopy. The molecular weight of the converted human insulin was further confirmed with SDS–18% PAGE, Matrix‐Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry (MALDI‐TOF‐MS) and the biological activity assay by HP‐RPLC. Copyright © 2014 John Wiley & Sons, Ltd.     

蛋白折叠液相色谱法中流动相对重组人干扰素-γ质量回收率的影响

蛋白折叠液相色谱法(PFLC)用于变性蛋白质复性并同时纯化时对流动相组成及其洗脱条件的要求远较通常的液相色谱法高。用端基为PEG-200的高效疏水作用色谱固定相对重组人干扰素-γ(rhIFN-γ)进行纯化并同时复性,详细研究了流动相组成、梯度洗脱模式和流速对rhIFN-γ质量回收率和活性的影响。分别以3.0 mol/L (NH4)2SO4 +0.05 mol/L KH2PO4(pH 7.0)和0.05 mol/L KH2PO4(pH 7.0)为流动相A和B,采用35 min非线性梯度洗脱时,所得rhIFN-γ的质量回收率最高。     

用于变性蛋白质复性及同时纯化的简易型色谱柱的研制及其应用

研制出一种简易型色谱柱并通过装填大颗粒的疏水色谱填料对色谱柱的性能进行了考察,该柱的外形和操作如同传统的液相色谱柱,但它却在生物大分子分离方面有着和高效液相色谱相似的分辨率。另外,只要给该柱装填合适的固定相,比如疏水相互作用色谱固定相,便可用于蛋白质的复性及同时纯化。实验考察了该色谱柱的结构、操作和性能,包括柱压、柱寿命及对蛋白质的分辨率等。以溶菌酶为模型蛋白质,实验测得其在初始浓度为50.0 g/L时的质量回收率和活性回收率分别为(96.6±1.3)%和(101.1±6.0)%。这种简易型色谱柱价格低廉     

动力学因素对液相色谱分离整体蛋白的影响

依据液相色谱分离整体蛋白的效果与色谱柱柱长基本无关的事实,研究了动力学因素对疏水相互作用色谱(HIC)分离整体蛋白的影响。首次提出了用于线性梯度洗脱条件下蛋白分离的“条件板高”(H)概念,并将其用于动力学因素对分离整体蛋白的影响的表征。分别用常用的色谱柱和色谱饼对标准蛋白进行了分离,绘制了类似于van Deemter的“条件板高”对流动相线速(u)的曲线图。发现对应于色谱柱最低“条件板高”的适合线速约为色谱饼的1/5～1/15,且色谱饼的适合线速范围也较色谱柱宽得多。据此,用装填有HIC填料的色谱饼(10 mm×20 mm i.d.)在12 min内便可完全分离7种标准蛋白。还用装填有HIC填料的色谱饼对重组人粒细胞集落刺激因子(rhG-CSF)进行了复性并同时纯化,在50 min内,仅用一步色谱法就可获得纯度≥97%的rhG-CSF,其质量回收率为39%,比活＞1×108 IU/mg。可以预计,装填极细颗粒的刚性色谱填料的色谱饼可在高负荷条件下进行整体蛋白的高速和高分离度的分离、纯化并同时复性,达到“三高”。     

Refolding of urea‐denatured α‐chymotrypsin by protein‐folding liquid chromatography

An approach for re‐folding denatured proteins during proteome research by protein folding liquid chromatography (PFLC) is presented. Standard protein, α‐chymotrypsin (α‐Chy), was selected as a model protein and hydrophobic interaction chromatography was performed as a typical PFLC; the three different α‐Chy states – urea‐denatured (U state), its folded intermediates (M state) and nature state (N state) – were studied during protein folding. Based on the test by matrix‐assisted laser desorption/ionization time of flight mass spectrometry and bioactivity, only one stable M state of the α‐Chy was identified and then it was prepared for further investigation. The specific bioactivity of the refolded α‐Chy was found to be higher than that of commercial α‐Chy as the urea concentration in the sample solution ranged from 1.0 to 3.0 m ; the highest specific bioactivity at urea concentration was 1.0 m , indicating the possibility for re‐folding some proteins that have partially or completely lost their bioactivity, as a dilute urea solution was employed for dissolving the sample. The experiment showed that the peak height of its M state increased with increasing urea concentration, and correspondingly decreased in the amount of the refolded α‐Chy. When the urea concentration reached 6.0 m , the unfolded α‐Chy could not be refolded at all. Copyright © 2012 John Wiley & Sons, Ltd.     

谷胱甘肽键合柱对变性核糖核酸酶的复性研究

将氧化还原型谷胱甘肽(GSH/GSSG)共价键合到色谱固定相上, 实现了对变性核糖核酸酶(RNase)的复性. 实验发现, 谷胱甘肽键合柱具有典型的弱阳离子交换性质, 在离子交换(IEC)模式下能够对4种标准蛋白进行基线分离, 且具有较高的柱效. 当蛋白浓度为5 mg/mL, 流速为0.2 mL/min时, 在流动相中不加GSH/GSSG的条件下, GSH/GSSG柱对变性核糖核酸酶的活性回收率可达(39.5±3.8)%, 而普通IEC柱对变性核糖核酸酶的活性回收率几乎为0, 说明其对变性蛋白二硫键的正确对接具有明显的促进作用; 在收集液中加入GSH/GSSG后, 其活性回收率可达到(81.5±4.3)%. 本文结果对蛋白折叠液相色谱法的发展及降低蛋白复性成本具有一定的应用价值.     

Mechanism of simultaneously refolding and purification of proteins by hydrophobic interaction chromatographic unit and applications

The hydrophobic amino acid residues of a denatured protein molecule tend to react with the particles of the stationary phase of hydrophobic interaction chromatography (STHIC). These hydrophobic interactions prevent the denatured protein molecules from aggregating with each other. The STHIC can provide high enough energy to a denatured protein molecule to make it dehydration and to refold it into its native or various intermediate states. The outcome not only depends on the specific interactions between amino acids, the structure of STHIC, but also depends on the association between the STHIC and mobile phase. The mechanism of protein refolding and the principle of its quality control by HPHIC were also presented. By appropriate selection of the chromatographic condition, several denatured proteins can be refolded and separated simultaneously in a single chromatographic run. A specially designed unit, with diameter much larger than its length, was designed and employed for both laboratory and preparative