Affinity Purification of Insulin by Peptide-Ligand Affinity Chromatography

The affinity heptapeptide(HWWWPAS)for insulin,selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column.The column was used for the affinity purification of insulin from protein mixture and commercial insulin preparation.It was observed that the minor impurity in the commercial insulin was removed by the affinity chromatography.Nearly 40 mg of insulin could be purified with the 1-mL affinity column.The results revealed the high specificity and capacity of the affinity column for insulin purification.Moreover,based on the analysis of the amino acids in the peptide sequence,shorter peptides were designed and synthesized for insulin chromatography.As a result,HWWPS was found to be a good alternative to HWWWPAS,while the other two peptides with three or four amino acids showed weak affinity for insulin.The results indicated that the peptide sequence of HWWWPAS was quite conservative for specific binding of insulin.

SYNTHESIS OF INTERFERON-α_A MONOCLONAL ANTIBODY PACKING MATERIAL IN HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY AND PURIFICATION OF RECOMBINANT HUMAN INTERFERON-α_A

A new way for the synthesis of human interferon—α_A monoclonal antibody (IFN-α_A-McAb) bound to silica gel packing material in high-performance affinity chromatography (HPAFC) has been developed. The high coupling efficiency and specific activity of IFN—α_A-McAb can be obtained by activated diol-silica gel with activating agent. After purification using this packing material in HPAFC, the specific activity of recombinant human interferon-α_A (rIFN-α_A) rose up to 1.03×10~7IU/mg protein and the purification efficiency is appoximately 100 times.

Separation and Purification of Thrombin-like Enzymes by Affinity Adsorbents

An affinity adsorbent, benzamidine Sepharose 4B, was used to separate and purify thrombin like enzymes. The p aminobenzamidine as a specific ligand was coupled to the matrix-Sepharose 4B. The recombinant thrombin like enzyme-defibrase was used as a model in order to evaluate the efficiency of this biospecific affinity adsorbent. The homogeneity of the enzyme preparation was comfirmed as one band on sodium dodecyl sulfate polyacrylamide gel electrophoresis.

THE BINDING BEHAVIOUR OF IMMOBILISED LOW MOLECULAR WEIGHT LIGAND WITH PEPTIDES IN BIOSENSOR-BASED SYSTEM

In this study a hovel metal ion affinity ligand was immobility onto the sensor chip. Three poly-histidine peptides were used to study the interaction of tile peptides and the immobilised metal ion affinity ligand via biosensor system . The results obtained in this study indicate that the affinity of immobilised Ni(Ⅱ) ion affinity ligand for these peptides appear to be related to the arrangement of the histidine residues in the peptides. This study first documents the application of biosensor technique for paptide screening.

In situ synthesis and unidirectional insertion of membrane proteins in liposome-immobilized silica stationary phase for rapid preparation of microaffinity chromatography

Cell membrane affinity chromatography has been widely applied in membrane protein(MP)-targeted drug screening and interaction analysis.However,in current methods,the MP sources are derived from cell lines or recombinant protein expression,which are time-consuming for cell culture or purification,and also difficult to ensure the purity and consistent orientation of MPs in the chromatographic stationary phase.In this study,a novel in situ synthesis membrane protein affinity chromatography(iSMAC)method was developed utilizing cell-free protein expression(CFE)and covalent immobilized affinity chromatography,which achieved efficient in situ synthesis and unidirectional insertion of MPs into liposomes in the stationary phase.The advantages of iSMAC are:1)There is no need to culture cells or prepare recombinant proteins;2)Specific and purified MPs with stable and controllable content can be obtained within 2 h;3)MPs maintain the transmembrane structure and a consistent orientation in the chromatographic stationary phase;4)The flexible and personalized construction of cDNAs makes it possible to analyze drug binding sites.iSMAC was successfully applied to screen PDGFRβinhibitors from Salvia miltiorrhiza and Schisandra chinensis.Micro columns prepared by in-situ synthesis maintain satisfactory analysis activity within 72 h.Two new PDGFRβinhibitors,salvianolic acid B and gomisin D,were screened out with KD values of 13.44 and 7.39μmol/L,respectively.In vitro experiments confirmed that the two compounds decreasedα-SMA and collagen Ⅰ mRNA levels raised by TGF-βin HSC-T6 cells through regulating the phosphorylation of p38,AKT and ERK.In vivo,Sal B could also attenuate CCl_(4)-induced liver fibrosis by downregulating PDGFRβdownstream related protein levels.The iSMAC method can be applied to other general MPs,and provides a practical approach for the rapid preparation of MP-immobilized or other biological solid-phase materials.

β_2-Adrenoceptor affinity chromatography and its application in the screening of the active compounds from Semen Armeniacae Amarum

β2-Adrenoceptor (β2-AR) was purified from the rabbit lung tissue by sepharose-salbutamol affinity chromatographic column. To prepare the β2-AR stationary phase, β2-AR was evenly immobilized on the surface of macro-pore silica with a mild chemical coupling method through covalent bond. The reten- tion properties of β2-AR stationary phase were characterized by four ligands, salbutamol sulfate, noradrenaline bitartrate, adrenaline hydrochloride and propranolol hydrochloride, to establish the β2-AR affinity chromatography. Then, the method was used to screen the active compounds from the total extracts of Semen Armeniacae Amarum. The results showed that β2-AR on the surface of the sta- tionary phase could keep its original bioactivity and selectivity. Amygdalin retained in the chroma- tographic column was proved to be the active compound of the total extracts of Semen Armeniacae Amarum. Compared with the existing chromatographic screening approaches, this method showed a good stability and high selectivity. The active compounds which could interact with β2-AR in traditional Chinese medicine (TCM) could be screened efficiently by this method, providing a new way to screen the active compounds in complicated samples such as TCM.

Expression,purification and identification of LBD domain of human PPARδ in E.coli

Peroxisome proliferator-activated receptors （PPARs） are ligand-activated transcription factors known to play a pivotal role in regulations of metabolism. In order to yield soluble ligand binding domain of PPARδ （PPARδLBD） for screening ligands, the cDNA was amplified using total RNA from HepG2 cells by RT-PCR. Then the enzyme-digested product was inserted . downstream of the malE gene in the vectorpMAL-p2x, which encoded maltose-binding protein （MBP）, resulting in the expression of an MBP-PPARδLBD fusion protein. The recombinant plasmid was transformed into E. coli TBI that was cultured shakily at 30 ℃, 200 r/min and induced by 0.4 mmol/L IPTG for 6 h. The cells were harvested by centrifugation and broken by sonication. The expressed fusion protein was soluble and accounted for 0.31 of the total protein in the supernatant. Western blot analysis showed that the expressed MBP-PPARδLBD could bind to anti-MBP-antibody. The MBP-PPARδLBD fusion protein of 77 kDa and the PPARδLBD protein of 34 kDa were obtained by amylose-resin affinity chromatography without or with digestion of Factor Xa. They were both homogeneity, judged by SDS-PAGE. The recombinant MBP-PPARδLBD and PPARδLBD protein with high purity is obtained, which provides the necessary material for screening and researching PPARδ ligands.

Purification and characterization of human anti-HBsAg Fab fragment produced by genetic engineering technology

Objective: To obtain pure human monoclonal antibody (mAb) Fab fragments against HBsAg with good biological activity by genetic engineering technology. Methods: The specific anti-HBsAg phagemid was selected from established combinatorial library and transfected into E. coil XL1-blue. Its expression was induced by isopropyl β-D- thiogalactopyranoside (IPTG). The crude Fab supernatant was obtained after E. coli cells were frozen at - 20℃ and thawed repeatedly along with centrifugation. The goat anti-human IgG Fab was prepared by immunizing the goat with purified human IaG Fab. The affinity chromatography column with goat anti-human IgG Fab and GammaBind Plus Sepharose was obtained. The crude Fab super- natant was purified with affinity chromatography and the purity was assessed with SDS-PAGE and Western-blot, and biological activity was evaluated by Dot-blot test. Results: SDS-PAGE of the purified Fab displayed a side band, verified to be the Fab band by Western-blot test. Dot-blot test demonstrated that the purified Fab fragments posses good affinity to HBsAg. Conclusion: The success in purification of human anti-HBsAg Fab fragments with good biological activity makes it possible to be used as future therapeutic agents.

色谱技术在抗体分离纯化中的应用进展

抗体作为一类重要的生物药物,在疾病诊断和治疗等方面拥有广阔的前景。抗体药物的需求逐年上升,生产规模不断扩大,下游抗体纯化已经成为抗体药物生产的瓶颈。色谱技术具有选择性好、分离效率高等优点,在抗体纯化领域占据主导地位。抗体分离纯化流程一般包括样品的粗提、粗提物精制和抗体精纯3个步骤,每个步骤都涉及色谱分离技术。目前已有多种色谱技术(如亲和色谱、离子交换色谱、疏水作用色谱、混合模式色谱以及新型的温敏色谱等)应用于抗体的分离纯化。本文介绍了近年来国内外各种色谱技术在抗体分离纯化方面所取得的研究进展,并对抗体色谱分离技术的未来发展趋势进行了展望。

Ca^(2+)-亚氨二醋酸金属离子亲和色谱法吸附内毒素(英文)

Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.

二化螟体内乙酰胆碱酯酶的分布及纯化方法

研究了二化螟Chilosuppressalis乙酰胆碱酯酶 (AChE)的体躯和亚细胞分布 ,并用凝胶过滤层析和 2种亲和层析方法从二化螟幼虫体内分离、纯化乙酰胆碱酯酶。结果表明 :二化螟幼虫乙酰胆碱酯酶的活性主要集中于头部和胸部 ,而成虫胸部乙酰胆碱酯酶的活性最低 ,显著低于头部和腹部。成虫体内AChE的活性明显高于幼虫。在亚细胞的分布上 ,乙酰胆碱酯酶主要位于膜上 (86 % ) ,近 46 %的活性存在微粒体中。在 3种纯化乙酰胆碱酯酶的方法中 ,以 3 羧基苯基 乙基二甲基铵作配体的亲和层析法纯化效果最佳 ,乙酰胆碱酯酶的最高纯化倍数为 5 36 0 5倍 ,产率 30 46 %。

亲和色谱法的进展

概述了亲和色谱法分离机理、色谱填料及其应用的新进展，着重介绍了亲和固定相中配基发掘的新途径。全文包括66篇文献。

凝血酶的亲和层析纯化技术

以新鲜猪血为原料 ,采用离心、激活、沉淀等技术提取出粗凝血酶 ,利用化学方法将分子量范围在 6KD左右的肝素连接到经溴化氰活化的 Sepharose CL- 6B树脂上 ,制成亲和树脂 ;采用亲和方法 ,从粗酶中纯化得到猪凝血酶。活性测定表明 ,在保持酶的底物专一性的同时 ,凝血酶的比活上升了 32 .5倍左右。计算总活力回收率约 5 0 .6%。同时对肝素亲和层析柱的制备以及洗脱方法进行了探讨。

抗核糖核酸酶抑制因子抗体的制备与纯化

目的 :制备并纯化抗核糖核酸酶抑制因子 (RI)的抗体。方法 :从人胎盘中提取RI,经亲和层析纯化后免疫家兔制备RI抗体。用rProteinASepharoseFastFlow层析对抗RI抗体进行纯化 ,并用SDS PAGE、ELISA及Westernblot等进行鉴定。结果 :制备并纯化了抗RI抗体 ,经SDS PAGE分析达到了电泳纯。结论 :获得了效价高、特异性强、稳定性好的抗RI抗体 。

IDA型Cu^(2+)-螯合亲和膜色谱法对牛肝过氧化氢酶纯化的研究(英文)

首次采用以改性纤维素为基质、亚氨二乙酸（ＩＤＡ）为取代配基的铜离子螯合膜色谱法对牛肝过氧化氢酶（ＢＬＣ）的分离纯化进行了研究。缓冲液的ｐＨ值对ＢＬＣ与螯合配基的结合影响显著。在选定的色谱条件下，ＢＬＣ粗酶液经ＩＤＡ型Ｃｕ２＋－螯合膜色谱柱一步纯化，比活性平均提高４．７倍，回收率为６７．７％。金属螯合膜色谱柱可用含０．２ｍｏｌ／Ｌ的咪唑或５０ｍｍｏｌ／ＬＥＤＴＡ－１ｍｏｌ／ＬＮａＣｌ的缓冲液再生，反复使用，后者比前者对柱子的再生效果更好。

鸡血浆纤维连接蛋白的提纯及酶联免疫吸附检测方法的建立

利用纤维连接蛋白 (FN)与明胶特异结合的特点 ,用明胶亲和层析结合电泳裁胶的方法提纯鸡血浆FN并制备了兔抗鸡FN抗血清。纯化的FN经凝胶电泳鉴定为一条蛋白带且与人FN在同一位置上 ,亚单位分子量约 2 3 0KDa ;经免疫鉴定 ,提纯鸡血浆FN与兔抗人FN抗体有交叉反应性。用兔抗鸡FN抗体包被捕捉抗原 ,建立了检测鸡血浆FN的双抗体酶联免疫吸附法(ELISA) ,此法具有操作简单、特异性强、灵敏度高的特点 ,适用于鸡血浆FN的检测。鸡血浆FN的提纯及其检测方法的建立 ,为FN在兽医领域的进一步研究和应用奠定了基础。

IDA型固定化镍离子金属螯合亲和膜色谱对人血清白蛋白的分离纯化

采用自制的固定化镍离子亚氨二乙酸(IDA)型复合纤维素金属螯合膜色谱对药用人血清白蛋白的进一步纯化进行了研究。考察了pH对HAS吸附效果的影响。经一步纯化,商品药用HSA中的许多杂蛋白可被除去,经毛细管电泳分析,纯度与Sigma公司的电泳纯HSA相当,回收率可达85%以上。纯化蛋白液中的镍离子经过自制的N,N,N′三羧甲基乙二胺(TED)型螯合柱处理后可较好地除去。

新型分离纯化技术—亲和超滤及其应用

亲和超滤技术是把亲和层析的高选择性和超滤技术的高处理能力相结合的一种新型能大规模进行生物特征物质分离提纯的技术.简要介绍了亲和超滤技术的原理和特征,详细介绍了亲和超滤技术在生物工程和制药工程上的应用.随着亲和超滤技术的发展,应用领域将会不断扩大,将会极大地推动热敏物质(蛋白质、酶、维生素、中草药等)和分子量相近物质(同分异构体、同系物等)分离技术的发展.

大豆凝集素的分离纯化及活性鉴定

以D-半乳糖胺为配基、FF-sepharose 4B为固定相,制备大豆凝集素亲和层析填料.分离和纯化大豆中的大豆凝集素蛋白,测定其纯度、免疫原性和凝集活性,并与美国Sigma公司的标准品比较.结果表明:每毫升GalN-FF-Sepharose-4B层析填料能结合10 mg大豆凝集素;纯化获得的大豆凝集素分子量为30 000;SDS-PAGE测定纯度大于98%;Western blot结果为阳性;1 mg/mL SBA血集效价为1/210;其纯度、免疫原性和凝集活性等指标与大豆凝集素标准品相同,与理论值相符.

亲和分离技术中亲和配基的研究进展

亲和分离技术在蛋白质的分离纯化过程中发挥着越来越重要的作用,开发合适的配基是亲和分离的关键。按生物大分子亲和配基、小分子亲和配基、金属亲和配基三大类对亲和配基的研究情况进行综述,重点介绍其发展现状、作用机理以及目前存在的主要问题,并对亲和配基未来发展进行展望,旨为将其更好地应用于实际生产。