扇叶铁线蕨凝集素的糖蛋白特性

扇叶铁线蕨叶片组织经磷酸盐缓冲液浸提,硫酸铵沉淀,再经过DEAE-Sepharose—FF和Sephadex G-100层析纯化,得到扇叶铁线蕨凝集素(AFL)。其凝集活性依赖于Ca^2 和Mn^2 ,经测定AFL,是一种分子质量为22000—22500的糖蛋白,分子中含有4．0％的中性糖,具有很高的耐热性,浓度为37．5μg ml^-1的AFL凝血活性可被甘露糖抑制,卵粘蛋白可完全抑制AFL的凝血活性。浓度为2．34μg ml^-1时引起兔血细胞凝集,并能凝集人的A、B或O型血细胞,对鳖的血细胞没有凝集作用。AFL能凝集藻类细胞、酿酒酵母细胞及经过热处理的枯草芽孢杆菌。在AFL的氨基酸组成中不含Tyr。研究结果表明,该凝集素具有糖蛋白的特性。     

红花菜豆凝集素的糖结合专一性

经肼解、Ｂｉｏ－Ｇｅｌ Ｐ－２柱层析、ＮａＢ＾３Ｈ４和ＮａＢＨ４还原,制备各种来源的、氚标记在还原末端的、还原末端为Ｎ－乙酰氨基葡萄糖醇的混合寡糖,经Ｂｉｏ－Ｇｅｌ Ｐ－４凝胶柱分离,以及用糖苷酶酶解,制备了各种不同类型的氚标记的寡糖。这些寡糖在固定化的ＰＣＬ－Ｓｅｐｈａｒｏｓｅ柱上亲和层析,根据各种类型寡糖在ＰＣＬ－Ｓｅｐｈａｒｏｓｅ柱上的层析行为,确定红花菜豆（矮生红花变种）凝集素（ＰＣＬ）的     

精子膜麦芽凝集素结合糖蛋白抗原某些特性的研究

应用自制的抗牛精子膜麦芽凝集素结合糖蛋白血清,对兔、人、小鼠和仓鼠精子进行了免疫细胞化学定位,结果各种动物精子均呈阳性反应,且以精子顶体区标记最强,与麦芽凝集素亲和细胞化学的标记结果相似。用抗血清处理地鼠精子,再与同种卵子进行体外结合试验,结果精子与卵于透明带的结合受到显著抑制、本实验的结果提示,牛精子膜麦芽凝集素结合糖蛋白抗原具有种间交叉反应性,并可能在精子与卵子透明带结合过程中具有重要作用。     

半夏凝集素的糖结合活性研究

半夏凝集素可与甘露聚糖结合。本文以ＰＴＬ与＾１２５Ｉ标记的甘露聚糖的结合活性为指标,观察了一些金属离子对ＰＴＬ的糖结合活性的影响,并对ＰＴＬ的糖结合专一性作了较系统的研究。结果表明常见的金属离子或ＥＤＴＡ对其糖结合活性无显著影响,但Ｋ＾＋可明显增加ＰＴＬ的糖结合活性。大多数单糖,二糖不抑制ＰＴＬ与甘露聚糖的结合,但一些疏水配基形成的糖苷可产生显著的抑制效应。ＰＴＬ专一与高甘露糖型糖链结合。     

凝集素碎片的糖结合活性

用固相合成法分别合成了羊蹄甲、小扁豆和欧洲百脉根３种植物凝集素中的某些糖结合活性部位的肽段。用毛细管电泳法观察到这些肽段和拟糖蛋白以及寡糖之间有一定的结合能力,而且表现出相对的专一性。     

基于凝集素-糖蛋白特异结合的特性筛选与鉴定空肠弯曲杆菌NCTC11168株糖蛋白

[目的]从空肠弯曲杆菌NCTC11168菌株中筛选糖蛋白.[方法]本实验基于凝集素-糖蛋白特异结合的特性,先用免疫印迹的方法确定空肠弯曲杆菌内糖蛋白能与凝集素SBA特异结合,再用包被有凝集素SBA的磁珠捕获样品中的潜在糖蛋白,通过N-乙酰半乳糖胺竞争性洗脱及双向电泳分离,最后利用串联质谱鉴定捕获的糖蛋白.[结果]质谱分析共鉴定到22种空肠弯曲杆菌蛋白,其中至少5种为已报道糖蛋白,包括Cj0633在内的17种为迄今为止未知的潜在糖蛋白.[结论]这种糖蛋白筛选策略可用于细菌糖蛋白的分离鉴定.     

竹叶青蛇毒凝集素的糖结合性质

本文利用竹叶青蛇毒凝集素和去唾流酸的ａ１－酸性糖蛋白之间相互作用的研究系统,对ＴＳＬ的糖结合条件及结合性质作了更为全面深入的研究。研究结果表明,在ｐＨ５－１０的范围内,ＴＳＬ的糖结合活性基本不变,具有较广泛的ＰＨ适应性;ＴＳＬ的温度适应范围较窄,５０℃保温２小时活性便基本更新换代。在简单糖类中,半乳糖是最强的糖结合活性抑制剂。就吡喃型已糖而言,以Ｃ－３和Ｃ－４位置上的取代基的取向最为重要,特别是Ｃ     

高及低转移潜能小鼠肝癌细胞株糖蛋白凝集素结合特征的研究

为探讨肿瘤转移与细胞表面的糖结构的关系,对小鼠肝癌细胞的高、低淋巴道转移株ＨＣａ－Ｆ和ＨＣａ－Ｐ进行了蛋白质电泳及经蛋白质印迹术后的５种凝集素（ＣｏｎＡ、ＷＧＡ、ＵＥＡ、ＳＢＡ、ＰＮＡ）结合糖蛋白谱的对比分析。结果表明：高、低转移两株细胞的ＳＤＳ－ＰＡＧＥ谱基本相同;Ｃｏｎ Ａ特异结合糖蛋白共有５种（￣７２,８０￣９０,￣１０４,￣１５０,￣２００ｋＤ）;其中较明显的差异为￣７２ｋＤ ＣｏｎＡ特异     

应用生物素标记的凝集素分析登革Ⅱ型病毒糖蛋白

应用十二种生物素标记的凝集素,分析了经SDS-PAGE和电转印分离的登革Ⅱ型病毒(D_2V)糖蛋白。结果表明:D_2V的包膜糖蛋白E可与三种D-甘露糖特异的凝集素(conAPSA及LCA)结合,提示E蛋白的寡糖链为高甘露糖型。D_2V的糖基化非结构蛋白NS_1可与两种D-甘露糖特异的凝集素conA及LCA结合,提示NS_1的寡糖链亦为高甘露糖型。实验结果还显示了一些可能为C6/36细胞感染D_2V后新合成、合成量增加或减少以至完全受抑制的糖蛋白成分,有关这些糖蛋白的性质、功能、意义尚不清楚。在本实验条件下,这种生物素标记凝集素印迹法证明了其敏感性和糖基特异性,可以作为分析各种微量含糖大分子的一种实用方法。     

白桂木凝集素的纯化与性质的研究

白桂木种子粉经抽提、３０～６０％饱和度硫酸铵沉淀和亲和层析,已获得纯化的白桂木凝集素（Ａｒｔｏｃａｒｐｕｓｈｙｐａｒｇｙｒｂｕｓｌｅｃｔｉｎ）。浓度梯度ＰＡＧＥ,显示基本是均一的蛋白质带,分析表明,它是由分子量为１５０００和１９０００两种亚基组成,Ｎ端为精氨酸和丙氨酸,ｐＩ９．１０、８．４５、８．１０,中性精含量约６．９％,氨基糖约０．４％,能凝集多种动物红细胞和人Ａ、Ｂ、Ｏ和ＡＢ血型红细胞,凝集活力受Ｇａ１ＮＡｃ、Ｇａｌ和棉子糖的抑制,对热较敏感,在ｐＨ４．５～９．５的范围内．ｐＨ的改变不影响它的血凝活力。     

Purification and Characterization of Cotton Lectin

Defatted seeds of wilt-disease resistant were extracted overnight with PBS at 4 ℃. After centrifugation. 90% saturated (NH4)2SO4 was added to the supernatant. The precipitates were dialysed against H2O, then lyophilized. The purified lectin was obtained by DEAE-cellulose ion-exchange chromatography, Sephadex G-100 filtration, and Sepharose 4B-Hog thyroglohulin affinity chromatography. The activity of the lectin was tested with fresh rabbit erythrocyte in each step of the procedure, and the active part was collected. This sample demonstrated single band on PAGE, SDS-PAGE and HPLC. The lectin was a glycoprotein. It contained 1.5% of neutral saccharide and its molecular weight was 63000 determined by Sephadex G-100 filtration. The N-terminal amino acid of the lectin was Val. The lectin showed no specific agglutination with any type of human erythrocytes. The hemagglutinaition activity could be inhibited by galactose and hog thyroglobilin, and depended on Ca2+, Mn2+, especially on Ca2+, not Mg2+. Its biological activity lost at 65 ℃ for S min. This lectin is used as a mitogen for human peripheral blood lymphocytes.     

肾综合征出血热病毒糖蛋白的提纯和鉴定

以感染肾综合征出血热病毒(HFRSV)的Vero E6细胞为材料,用免疫亲和层析结合制备聚丙烯酰胺凝胶电泳(PAGE)从感染细胞中提纯了HFRSV两种糖蛋白。先用免疫亲和层析从感染细胞的粗制抗原中获得含有四种蛋白的混合液,用[~3H]-氨基葡萄糖在感染细胞中标记病毒糖蛋白,观察到[~3H]-氨基葡萄糖只结合入78K和57K的病毒蛋白。再用制备SDS-PAGE从HFRSV混合液中提纯78K和57K两种蛋白。实验证明这两种糖蛋白均具中和抗原决定簇,57K的糖蛋白尚具血凝活性,初步鉴定表明这两种糖蛋白相当于文献报道的HFRSV G_1和G_2。     

红桂木凝集素的纯化与性质研究

红桂木（Ａｒｔｏｃａｒｐｕｓｌｉｎｇｎａｎｅｎｓｉｓ）、俗名胭脂,属桑科桂木属,为亚热带、热带植物．红桂木种子含丰富的红桂木凝集素（Ａｒｔｏｃａｒｐｕｓｌｉｎｇｎａｎｅｎｓｉｓｌｅｃｔｉｎ,ＡＬＬ）,但迄今国内外均未见关于它的报道．我们采用Ｇａｌ－Ｓ...     

Glycoproteins of the Chromaffin Granule Membrane: Separation by Two-Dimensional Electrophoresis and Identification by Lectin Binding

The proteins of highly purified chromaffin-granule membranes were separated by one- or two-dimensional electrophoresis, then transferred to nitrocellulose sheets; glycosylation was investigated by binding of several different radioiodinated lectins. Over 20 different glycosylated components were identified; comparison with mitochondrial and microsomal fractions suggested that most of the major glycoproteins are genuine components of the chromaffin granule membrane, rather than contaminants originating in other organelles. Two-dimensional electrophoresis revealed heterogeneity within several of the glycoproteins, and this is ascribed to differences in the state of glycosylation, on the basis of shifts in electrophoretic mobility produced by treatment with neuraminidase. Neuraminidase treatment of chromaffin granule membranes also enhances the binding of many lectins. The identities of the lectin-binding bands are discussed: neither cytochrome b561 nor the F1-like ATPase appears to be glycosylated. Chromogranin A, although a glycoprotein, does not bind any of the lectins tested, but a number of concanavalin-A binding proteins, as well as dopamine beta-hydroxylase, are present in the chromaffin granule lysate.     

旋扭山绿豆（Desmodiumintortum）凝集素的纯化与特性

旋扭山绿豆（Ｄｅｓｍｏｄｉｕｍｉｎｔｏｒｔｕｍ）凝集素的纯化与特性彭建宗,程双奇,陈兆平,莫熙穆（华南师范大学生物系,广州５１０６３１）关键词凝集素;旋扭山绿豆;亲和层析;糖蛋白豆科植物和根瘤菌之间的共生结瘤固氮关系早有报道。例如大豆只被Ｂ．仰。６。...     

三齿草藤(Vicia bungei Ohwi)凝集素的亲和层析纯化及其部分性质的研究

用Sephadex G-100或猪甲状腺球蛋白-对氨基苯砜乙基-交联琼脂作亲和吸附剂,均可从三齿草藤(Vicia Bungei Ohwi)的种子中分离纯化出三齿草藤凝集素。该凝集素经连续或不连续系统聚丙烯酰胺凝胶电泳均显示出单一蛋白带;糖蛋白染色法证实为糖蛋白;SDS-聚丙烯酰胺凝胶电泳测定其分子量为24,600,凝集素浓度为1.95微克/毫升时就能凝集兔红细胞;但对人ABO型血细胞不发生凝集作用;其对兔红细胞的凝集作用可被D-Man、D-GlcNA和D-GIC所抑制;它也是一种促有丝分裂原。     

同步纯化人心肌肌钙蛋白T、I

同步纯化人心肌肌钙蛋白Ｔ、Ｉ李志梁付朝平钱学贤陆青王素华黎梅兰（第一军医大学珠江医院心内科,广州５１０２８２）关键词心肌肌钙蛋白Ｔ;心肌肌钙蛋白Ｉ;同步纯化收稿日期：１９９６－０４－１７;接受日期：１９９６－０８－２７。心肌肌钙蛋白包括３种不同的蛋白...     

Interconversion of the Specificities of Human Lysosomal Enzymes Associated with Fabry and Schindler Diseases

The human lysosomal enzymes α-galactosidase (α-GAL, EC 3.2.1.22) and α-N-acetylgalactosaminidase (α-NAGAL, EC 3.2.1.49) share 46% amino acid sequence identity and have similar folds. The active sites of the two enzymes share 11 of 13 amino acids, differing only where they interact with the 2-position of the substrates. Using a rational protein engineering approach, we interconverted the enzymatic specificity of α- GAL and α-NAGAL. The engineered α-GAL (which we call α-GAL^SA) retains the antigenicity of α-GAL but has acquired the enzymatic specificity of α-NAGAL. Conversely, the engineered α-NAGAL (which we call α-NAGAL^EL) retains the antigenicity of α-NAGAL but has acquired the enzymatic specificity of the α-GAL enzyme. Comparison of the crystal structures of the designed enzyme α-GAL^SA to the wild-type enzymes shows that active sites of α-GAL^SA and α-NAGAL superimpose well, indicating success of the rational design. The designed enzymes might be useful as non-immunogenic alternatives in enzyme replacement therapy for treatment of lysosomal storage disorders such as Fabry disease.