用亲和层析法分离纯化降纤酶

目的用亲和层析法从尖吻蝮蛇蛇毒中分离纯化降纤酶。方法用离子交换色谱、单克隆抗体亲和色谱技术进行分离纯化。结果得到电泳纯的降纤酶，其分子量为36000。结论用单克隆抗体亲和色谱法纯化降纤酶是切实可行的。     

长白山白眉蝮蛇血凝酶的分离纯化研究

摘 要 目的：建立一种分离纯化长白山白眉蝮蛇血凝酶的方法。方法: 先后采用分子筛层析法、离子交换色谱法、肝素 Sepharose亲和层析法从长白山白眉蝮蛇蛇毒中分离纯化得到一种具有有凝血活性的酶成分,并采用SDS-Page法、RP-HPLC法测定其纯度,凝胶电泳法(SDS-Page)考察其对牛纤维蛋白原的作用方式、高效空间排阻色谱法（HPSEC）测定其相对分子质量,等电聚焦电泳分析法（IEF）测定其等电点,Lowry法测定其蛋白浓度。结果: 从长白山白眉蝮蛇蛇毒中分离纯化了一种凝血酶成分,SDS-Page显示为一条带,HPLC得到单一的色谱峰,该酶只作用于纤维蛋白原的α链,其相对分子质量为32.2 kD,等电点为5.21,此酶具有体外凝血活性。结论:该方法可用于长白山白眉蝮蛇血凝酶的分离纯化。     

白唇竹叶青蛇(Trimeresurus albolabris)毒降纤酶的分离纯化以及性质

目的从白唇竹叶青蛇(T.albolabris)毒中分离纯化无出血作用的降纤活性组分,探讨其理化性质及部分生物功能。方法用DEAE-SephadexA-25,SephadexG-100和CM-SephadexC-50三步色谱法进行分离纯化。SDS-PAGE和HPLC鉴定其纯度和相对分子质量,平板法测定其降纤活性。结果从白唇竹叶青蛇毒中分离纯化获得单一的降纤组分,能迅速水解纤维蛋白原或纤维蛋白原Aα链,缓慢水解Bβ链,而对γ链无作用,SDS-PAGE鉴定其相对分子质量为56000。EDTA能抑制其纤维蛋白原水解活性,而PMSF、β-巯基乙醇对其活性无影响,提示该组分为单链α金属蛋白酶。结论从白唇竹叶青蛇毒中分离纯化得到1种无出血作用且降纤活性强的新蛇毒降纤酶。     

白眉蝮蛇蛇毒纤溶酶的分离纯化

目的用白眉蝮蛇蛇毒分离纯化纤溶酶。方法利用离子交换层析、亲和层析、分子筛层析技术进行分离纯化纤溶酶。结果得到了电泳纯的纤溶酶,其相对分子质量为24000。结论该工艺可以快速地分离纯化白眉蝮蛇蛇毒纤溶酶：     

长白山白眉蝮蛇蛇毒中类凝血酶的分离纯化方法研究

目的:研究长白山白眉蝮蛇蛇毒中类凝血酶的简单分离纯化方法。方法:采用DEAE-Sephadex A-25及Sephadex G-25层析的方法,比较二者对长白山白眉蝮蛇蛇毒中类凝血酶简单分离纯化的效果。结果:从长白山白眉蝮蛇蛇毒中分离出类凝血酶,SDS-PAGE电泳显示为一条带,分子量大约为35.5kDa,达到电泳纯。理化性质研究表明,此类凝血酶具有体外凝血活性,体外凝血酶比活力为12.57IU.mg-1,用N-苯甲酰-L-精氨酸乙酯盐酸盐测得该酶的精氨酸酯酶比活力为137.65IU.mg-1。用蛋白酶抑制剂和乙二胺四乙酸对该酶进行抑制实验,结果表明该酶属于丝氨酸蛋白酶,而不是金属蛋白酶。结论:本方法可用于长白山白眉蝮蛇蛇毒中类凝血酶的分离纯化。     

白眉蝮蛇蛇毒的分离纯化及综合利用

目的促进蛇毒的有效、综合利用。方法在分离纯化白眉蝮蛇蛇毒中降纤酶的试验过程中,同时分离纤溶酶。结果主要成分降纤酶的回收率为55.80%,纤溶酶的回收率为20.40%。结论该方法实现了对蛇毒宝贵资源的综合利用,为其综合开发利用探索了一条有效途径。     

乌苏里蝮蛇毒一种C-型凝集素相关蛋白的分离、纯化及活性测定

目的从乌苏里蝮蛇蛇毒中分离纯化得到具有促凝血活性的C-型凝集素相关蛋白。方法利用IDA-Sepharose FF亲和色谱作为独立的蛋白分离纯化手段,并且结合Sephadex G-100,Sephadex G-50凝胶过滤色谱从乌苏里蝮蛇蛇毒中分离得到一个新的蛋白组分。结果该组分经还原和非还原SDS-PAGE电泳鉴定结果显示为均一的单一条带,即C-型凝集素相关蛋白,相对分子质量约为15.7 kD。结论经过一系列的分离和纯化,能够从乌苏里蝮蛇蛇毒中提取到C-型凝集素相关蛋白组分。     

长白山白眉蝮蛇蛇毒纤溶酶的纯化

从长白山白眉蝮蛇蛇毒中纯化具有溶栓功效的纤溶酶。方法：用 ＤＥＡＥ Ｓｅｐｈａｄｅｘ Ａ５０离子交换、Ｓｅｐｈａｄｅｘ Ｇ７５凝胶过滤层析和 ＤＥＡＥ Ｓｅｐｈａｄｅｘ Ａ ５０三步柱层析分离方法,对长白山白眉蝮蛇蛇毒进行分离纯化,得到了一种纤溶酶活性组分。结果：经ＳＤＳ－聚丙烯酰胺凝胶电泳和基质辅助激光解吸电离飞行时间质谱表征该酶为单一蛋白,其分子量为 ２３．３６７ ｋＤ。结论：为进一步研究其结构和功能提供了可靠依据。     

尖吻蝮蛇毒小分子多肽的分离及抗血小板聚集作用

目的从尖吻蝮蛇毒中分离纯化一种抗血小板聚集小分子多肽,研究其理化性质以及对ADP、胶原、凝血酶诱导的血小板聚集反应的影响。方法经SephadexG-75凝胶过滤,超滤,DEAE-SepharoseCL-6B离子交换层析法分离纯化蛇毒组分,采用高效液相鉴定纯度,用SDS-凝胶电泳(SDS-PAGE)测定其分子量,用比浊法测定其抗血小板聚集活性。结果从尖吻蝮蛇毒中分离相对分子质量约为7862u等电点为4.29的组分,该组分能抑制由ADP、胶原、凝血酶诱导的血小板聚集并成剂量依赖性。结论此法成功地从尖吻蝮蛇毒中纯化出抗血小板聚集组分。该组分与去整合素比较相似,可能属于去整合素家族。     

降纤酶肽图分析

目的采用反相高效液相色谱法测定尖吻蝮蛇降纤酶和白眉蝮蛇降纤酶肽图。方法将降纤酶样品用胰蛋白酶水解,酶解所得的肽段通过反相高效液相色谱法进行分析,采用C18色谱柱,以0.1%三氟乙酸为A相,乙腈-水-三氟乙酸(90∶10∶0.1)为B相进行梯度洗脱得到降纤酶肽图。结果降纤酶各个肽段都能得到很好的分离,白眉蝮蛇降纤酶和尖吻蝮蛇降纤酶肽图存在显著差异。结论本法简便、快速,可应用于不同蛇种来源降纤酶的鉴别,以减少临床不良反应的发生。     

降纤酶的聚乙二醇修饰及产物的纯化研究

研究了降纤酶的聚乙二醇修饰及纯化方法。采用正交法考察影响修饰的4个因素，确定了最佳条件。利用分子筛柱色谱得到了较高酶活力保留的修饰产物，SDS-PAGE检测为单一条带。     

Immunological properties of the fibrinolytic enzyme (fibrolase) from southern copperhead (Agkistrodon contortrix contortrix) venom and its purification by immunoaffinity chromatography

An antibody to the fibrinolytic enzyme in southern copperhead venom was produced by immunizing rabbits with chromatographically purified enzyme. The antibody was purified from rabbit blood by ammonium sulfate fractionation and protein-A affinity chromatography. The purified antibody reacted only with the fibrinolytic enzyme in southern copperhead venom as demonstrated by immunodiffusion and immunoelectrophoresis. Western immunoblotting revealed that several snake venoms, including Agkistrodon piscivorus conanti, Crotalus atrox, Crotalus basiliscus basiliscus, and Bothrops asper, cross-reacted with the antibody to varying degrees. However, Deinagkistrodon acutus showed no cross-reaction. Immobilized antibody has been used, in combination with molecular sieve chromatography, to purify the fibrinolytic enzyme from southern copperhead venom. In this two-step purification procedure, the enzyme was purified in good yield within two days. The specific activity of the enzyme purified by the immunoaffinity chromatography procedure is comparable with that of enzyme purified by a four-step chromatographic procedure. The mol. wt of the purified enzyme is approximately 23,000-24,000 as determined by SDS-PAGE. Interestingly, the enzyme purified by this two-step immunoaffinity chromatography procedure possesses virtually no hemorrhagic activity.     

蕲蛇酶与降纤酶的生物活性比较

目的比较蕲蛇酶和降纤酶在试管内的酶活力及在兔体血液凝固系统的生物活性。方法分别体外测定蕲蛇酶和降纤酶的相对分子质量(Mr)、蛋白质含量、精氨酸酯酶活力和凝血酶活力等。分别给家兔静脉注射蕲蛇酶0.75U/kg和降纤酶5U/kg,连续3d,比较给药前后纤维蛋白原含量、凝血酶时间、凝血酶原时间、部分凝血酶活酶时间、血小板数目、血小板聚集率、血栓长度及血栓重量的变化。结果蕲蛇酶Mr比较小(27000),且由2个Mr为15500的亚基构成,降纤酶Mr较大(40900),为单链蛋白质。0.75U蕲蛇酶和0.21U凝血酶相当;5U降纤酶约相当于1.4U凝血酶.蕲蛇酶的精氨酸酯酶活力为(973±14)μmolTAME/(mg.min),降纤酶的精氨酸酯酶活力为(1140±18)μmolTAME/(mg.min)。家兔实验,两者均能减少血栓形成及降低纤维蛋白原含量,但蕲蛇酶的药效比降纤酶强,其余指标无明显差异。结论蕲蛇酶与降纤酶不同,蕲蛇酶在生物体内(家兔)表现的药效比降纤酶强。     

水通道蛋白AqpZ在大肠杆菌中的表达及纯化

利用麦芽糖结合蛋白(Maltose binding protein,MBP)/多聚组氨酸和肠激酶组成的强亲水性双标签表达系统用于水通道蛋白Aquaporin Z(AqpZ)在大肠杆菌中的表达。通过PCR方法人工在AqpZ的3’端添加8个组氨酸标签后,定向克隆到载体pMAL-c5e中成功构建了双标签融合表达载体pMAL-c5e-AqpZ-HIS。通过IPTG诱导,融合蛋白MBP-AqpZ-HIS在Rosetta(DE3)宿主中以可溶形式表达,其上清表达量约为160 mg/L。表达产物在肠激酶作用下,融合蛋白的MBP标签被完全切除,经过一步的亲和层析获得高纯度的AqpZ-HIS。每升培养液可以获得约10 mg AqpZ-HIS纯蛋白。纯化得到的AqpZ-HIS在SDS-PAGE上的行为表明了AqpZ-HIS以4聚体形式存在。通过对色氨酸荧光光谱的研究推断出AqpZ-HIS也形成了正确的3级结构。因此,该表达系统为在大肠杆菌中表达水通道蛋白开辟了新的途径。     

AFFINITY CHROMATOGRAPHIC PURIFICATION OF PAPAIN A Reinvestigation

A reinvestigation of the affinity chromatographic method of purifying papain has been carried out. It has been reported that papain could be purified by taking advantage of the affinity of the enzyme for the insolubilized peptide inhibitor, agarose-Gly-Gly-Tyr(Bz)-Arg. Using pure tetrapeptide obtained commercially and standard coupling procedures, a significant purification of papain could not be achieved. Both active and nonactivatible enzyme bound to a column prepared in this manner were eluted together by the use of deionized water. An affinity medium with properties similar to those reported by Blumberg et al. was obtained by removal of the benzyl group on tyrosine prior to coupling with agarose. The deprotected tetrapeptide was also synthesized by an independent route and inhibition constants for the binding of the protected and deprotected tetrapeptide to papain were determined in kinetic experiments.     

玉米SOD的分离纯化与部分性质研究

目的建立1种高效而简单的玉米SOD分离纯化方法。方法采用初步提取、40%~80%硫酸铵分级沉淀、Cu2+螯合亲和色谱和DEAE-纤维素离子交换色谱处理的方法从玉米中提取SOD。结果获得了比活为1.18×104U/mg的SOD-A组分,活力回收率为11.7%;纯化后的SOD-A组分经PAGE和SDS-PAGE均为一条带;等电聚焦结果表明该组分的等电点为7.2;经鉴定,该组分属于Cu/Zn-SOD。稳定性研究表明,该组分对热、酸碱及常见变性剂(如尿素)的稳定性较好。结论利用Cu2+螯合亲和色谱和DEAE-纤维素离子交换色谱相结合的方法可以纯化得到高比活、稳定性好的玉米SOD-A组分。     

Affinity-purification of fibrinogenase with high proteolytic activity from <Emphasis Type="Italic">Agkistrodon halys</Emphasis> (Chinese) Venom

To purify and characterize the fibrinogenase with high proteolytic activity from Agkistrodon halys (Chinese) Venom. Monoclonal antibodies against fibrinogenase were prepared and a novel affinity chromatography equipped with a monoclonal antibody against fibrinogenase was developed and applied for the purification of fibrinogenases. The purified fibrinogenase was identified by fibrinolytic activity assay, and antithrombosis activity assay. HPLC chromatography and SDS-PAGE analysis demonstrated the uniformity and purity of the purified fibrinogenase. In comparison with a conventional A-50 chromatography method, affinity-purified fibrinogenase showed higher activity (3631 U mg(-1) vs 501 U mg(-1)). In addition, the physiological activity of the fibrinogenase both in vitro and ex vivo showed the purified fibrinogenase can specifically degrade beta-, gamma-fibrinogen and has a high anti-thrombotic activity. In conclusion, the purified fibrinogenase by affinity column were shown to be homogeneous and showed a high and specific proteolytic activity against beta-chains of fibrinogen molecules and antithrombosis activity.     

Isolation and characterisation of a cysteine protease (phytolacain G), from Phytolacca americana roots

Protein extracts obtained from dried and fresh roots of Phytolacca americana L. (Phytolaccaceae) were examined in order to identify and characterise individual proteins. The extracts were compared with a commercial pokeweed mitogen standard using SDS polyacrylamide gel electrophoresis (SDS-PAGE). A dominant protein, present in both the extracts and the pokeweed mitogen standard, was isolated by subsequent ammonium sulphate fractionation, anion exchange chromatography, gel filtration and SDS-PAGE. In this way it was purified 140-fold with about 20 % yield and 70-fold with about 13 % yield from dried and fresh roots, respectively. Its molecular mass as determined by gel filtration and SDS-PAGE was estimated to be about 25 kDa. Subsequent isoelectric focussing revealed one single protein band at pH 6.0. LysC digestion of the 25 kDa protein yielded several peptides which were subjected to micro-sequencing. Comparison with published sequences revealed that the protein isolated was phytolacain G, a cysteine protease previously isolated from unripe fruits of P. americana L. The enzyme showed a high affinity towards the oxidised insulin B-chain and was completely inhibited by trans-epoxysuccinyl- L-leucylamido(4-guanidino)-butane (E64). The purified phytolacain G showed "lectin-like" activities such as haemagglutination and mitogenic effects towards human lymphocytes.