天花粉凝集素糖结合专一性Ⅱ.

本文报道一些糖类、糖苷、糖蛋白和几种外源凝集素对标记天花粉凝集素和酸处理交联琼脂糖或胎盘细胞膜结合的影响。在低浓度时,所用的糖类中,乳糖是最强的抑制剂,蜜二糖和棉籽糖的抑制能力和乳糖相仿,而纤维二糖、蔗糖、麦芽糖,则无明显影响。三个所用的糖蛋白,它们的抑制活性以下列顺序递减:猪甲状腺球蛋白,人血清转铁蛋白,鸡卵白蛋白。未标记的天花粉凝集素和蓖麻凝集素,两者都专一地和半乳糖结合,它们都能竞争标记天花粉凝集素,而伴刀豆球蛋白A和半夏凝集素则不能竞争。由此,我们推测天花粉凝集素主要是和半乳糖结合,但与乳糖的结合能力最强,故推测其结合部位能容纳半乳糖和另一个单糖。     

刺芹侧耳下脚料多糖的纯化与结构解析

采用超滤分离结合乙醇沉淀的方法,从刺芹侧耳下脚料水提物中纯化获得一多糖组分PEP30。苯酚硫酸法检测其糖含量约为94.2%,HPSEC-MALLS-RI系统分析其重均分子量(Mw)为3.74×106Da,多分散系数为1.03,为窄分布样品。通过红外光谱、单糖组成分析、甲基化GC-MS分析和核磁共振技术对多糖的结构特征进行了研究。结果表明,PEP30为一种β-D-葡聚糖,其主链以β-(1→3)-糖苷键连接,支链以β-(1→6)-糖苷键连接,支链与主链上糖残基的摩尔比为1:3。     

天花粉凝集素糖结合专一性Ⅱ.

本文报道一些糖类、糖苷、糖蛋白和几种外源凝集素对标记天花粉凝集素和酸处理交联琼脂糖或胎盘细胞膜结合的影响。在低浓度时,所用的糖类中,乳糖是最强的抑制剂,蜜二糖和棉籽糖的抑制能力和乳糖相仿,而纤维二糖、蔗糖、麦芽糖,则无明显影响。三个所用的糖蛋白,它们的抑制活性以下列顺序递减:猪甲状腺球蛋白,人血清转铁蛋白,鸡卵白蛋白。未标记的天花粉凝集素和蓖麻凝集素,两者都专一地和半乳糖结合,它们都能竞争标记天花粉凝集素,而伴刀豆球蛋白A和半夏凝集素则不能竞争。由此,我们推测天花粉凝集素主要是和半乳糖结合,但与乳糖的结合能力最强,故推测其结合部位能容纳半乳糖和另一个单糖。     

一株人抗人A—血型物质单克隆抗体特异性的研究

本文对一株人抗人A-血型物质单克隆抗体,用定量免疫沉淀法以及ELISA研究其与多种单糖、双糖及寡糖的反应性,从而确定了其结合部位的结构特异性。实验发现其结合部位互补于含有双分子岩藻糖残基的A-t糖:这一研究进一步强调了含有双分子岩藻糖残基的A血型抗原决定簇的重要性。     

牛心朴子中三个新C21甾体配糖体

从宁夏产植物牛心朴子（Cymmehumkomarovii Al．IIjinski）须根的乙醇提取物中分离并鉴定了4个C21甾体配糖体：白前苷元C 3-O-β—D-吡喃葡萄糖基-（1→4）-β-D-吡喃葡萄糖基-（1→4）-α-L-吡喃磁麻糖基-（1→4）-β-D-吡喃毛地黄毒糖基-（1→4）-β—D-吡喃夹竹桃糖苷（1）,白前苷元A 3-O-β-D-吡喃葡萄糖基-（1→4）-β-D-吡喃葡萄糖基-（1→4）-α-D-吡喃夹竹桃糖基-（1→4）-β-D-吡喃毛地黄毒糖基-（1→4）-β-D-吡喃夹竹桃糖苷（2）,白前苷元C3-O-β—D-吡喃葡萄糖基-（1→4）-β-D-吡喃葡萄糖基-（1→4）-α—D-吡喃夹竹桃糖基-（1→4）-β-D-吡喃磁麻糖基-（1→4）-β-D-吡喃夹竹桃糖苷（3）,白前苷元A3-O-β—D-吡喃葡萄糖基-（1→4）-β-D-吡喃葡萄糖基-（1→4）-α—D-吡喃夹竹桃糖基-（1→4）-β-D-吡喃磁麻糖基-（1→4）-β-D-吡喃夹竹桃糖苷（4）,分别命名为komarosideI（1）,komarosideJ（2）,komarosideK（3）,komarosideL（4）,除化合物1外,其余化合物均为新化合物。     

传统中药漆姑草（Sagina japonica）中的C-27甾体成分

利用Diaion HP 20及硅胶柱层析进行化合物的分离,从乙酸乙酯萃取部位分离得到了4个化合物,借助多种光谱技术进行结构鉴定分别鉴定为(25R)-螺甾-5-烯-1β,3β-二醇1-O{O-α-L-鼠李吡喃糖苷-(1→2)-O-[β-D-木糖吡喃糖苷-(1→3)]1β-D-岩藻吡喃糖苷}(ophiopogonin D,1),(25R)-ruscogenin 1-O-[2-O-(乙酰基)-α-L-鼠李吡喃糖苷-(1→2)][β-D-木糖吡喃糖苷-(1→3)]-β-D-岩藻吡喃糖苷(2),(25R)-rascogenin 1-O-[3-0-(乙酰基)-α-L-鼠李吡喃糖苷-(1→2)][β-D-木糖吡喃糖苷-(1→3)]-β-D-岩藻吡喃糖苷(3),蜕皮甾酮(4).所有化合物均为首次从该植物中分得.     

牛心朴子中的三个新C21甾体配糖体

从宁夏产植物牛心朴子( Cynanchum komarovii Al. Iljinski.) 须根的乙醇提取物中分离并鉴定了4 个C₂₁ 甾体配糖体: 白前苷元C 3- O-β-D-吡喃葡萄糖基-(1→4 )-β-D-吡喃葡萄糖基-( 1→4-α-L-吡喃磁麻糖基-( 1→4 )-β- D-吡喃毛地黄毒糖基- (1→4 )-β- D-吡喃夹竹桃糖苷( 1) , 白前苷元A 3- O-β- D-吡喃葡萄糖基- (1→4 ) -β-D-吡喃葡萄糖基-(1→4 ) -α- D-吡喃夹竹桃糖基- (1→4 )-β- D-吡喃毛地黄毒糖基-(1→4 )-β- D-吡喃夹竹桃糖苷(2) , 白前苷元C 3- O-β-D-吡喃葡萄糖基-(1→4 )-β- D-吡喃葡萄糖基- (1→4 )-α- D-吡喃夹竹桃糖基-(1→4 ) -β-D-吡喃磁麻糖基-( 1→4 )-β- D-吡喃夹竹桃糖苷( 3) , 白前苷元A 3- O-β- D-吡喃葡萄糖基-(1→4 )-β-D-吡喃葡萄糖基-( 1→4 )-α- D-吡喃夹竹桃糖基- (1→4 ) -β-D-吡喃磁麻糖基- (1→4 )-β- D-吡喃夹竹桃糖苷( 4) , 分别命名为komaroside I (1) , komaroside J ( 2) , komaroside K ( 3) , komaroside L ( 4) , 除化合物1 外,其余化合物均为新化合物。     

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。     

无柄新乌檀中的配糖体

从无柄新乌檀乙醇浸膏的正丁醇部位分离得到7个已知配糖体化合物,经波谱分析为：喹诺酸-3-O-β-D-葡萄吡喃糖基(28→1)-β-D-葡萄吡喃糖酯(1),齐墩果酸-(28→1)-β-D-葡萄吡喃糖酯(2),熊果酸-(28→1)-β-D-葡萄吡喃糖酯(3),喹诺酸-3-O-β-D-葡萄吡喃糖基-(1→3)-6-去氧-β-葡萄吡喃糖苷(4),齐墩果酸-3-O-β-D-吡喃木糖基-(1→2)-β-D-葡萄吡喃糖基-28-O-β-D-葡萄吡喃糖酯(5),番木鳖甙(6),7-甲氧基-龙胆苦甙(7)。这些化合物均为首次从该属中分离得到。     

半夏凝集素的糖结合活性研究

半夏凝集素(PTL)可与甘露聚糖结合。本文以PTL与~(125)I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,井对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。     

Immunochemical studies on the combining site of the d-galactopyranose and 2-acetamido-2-deoxy-d-galactopyranose specific lectin isolated from Bauhinia purpurea alba seeds

The combining site of the Bauhinia purpurea alba lectin was studied by quantitative precipitin and precipitin inhibition assays. Of 45 blood group substances, glycoproteins, and polysaccharides tested, 35 precipitated over 75% of the lectin. Precursor blood group substances with I activity (Cyst OG 10% from 20% and Cyst OG 20% from 10%), desialized fetuin, and desialized ovine salivary glycoprotein, in which more than 75% of the carbohydrate side chains have dGalN Ac linked through α1 → to the OH group of Ser or Thr of a protein core, completely precipitated the lectin. The poorly reactive blood group substances after mild acid hydrolysis or Smith degradation, as well as sialic acid-containing glycoproteins after removal of sialic acid, had substantially increased activity so that more than 80% of the lectin was precipitated. Precipitability with various blood group substances and glycoproteins is ascribable to the terminal nonreducing dGalNAc, dGalβ1 → 3dGalNAc, dGalβ1 → 3 or 4dGlcNAc, and dGalβ1 → 3 or 4dGlcNAcβ1 → 3dGal determinants on the carbohydrate moiety. Of the monosaccharides tested for inhibition of precipitation, dGalNAc and its p-nitrophenyl and methyl α-glycosides were best. These compounds were four to five times better than the corresponding dGal compounds but methyl βDGalNAcp was only about 40% more active than methyl βdGalp. The α-anomers of p-nitrophenyl DGalNAcp and dGalp, were twice as active as the corresponding β-anomers. Methyl αDGalNAcp was four times as active as the β-anomer but the inhibitory power of the methyl α- and β-anomers of dGal were about equal. Among the oligosaccharides tested, dGalβ1 → 3dGalNAc and its tosyl derivatives were most active, the tosyl glycosides being about twice as active as dGalβ1 → 3dGalNAc, which was somewhat more active than dGalNAcα1 → 6dGal and dGalNAc, and 2.5 and 5 times as active as dGalNAcα1 → 3dGalβ1 → 3dGlcNAc and dGalNAcαl → 3dGa1, respectively (blood group A specific). These findings suggest that a subterminal dGalNAc β-linked and substituted on carbon 3 plays an important role in binding. Consistent with this inference are the findings that dGalβ1 → 3dGlcNAc and dGalβ1 → 6dGal were poorer inhibitors although dGalβ1 → 3dGlcNAc was two to three times as active as glycosides of dGal. Oligosaccharides with terminal nonreducing dGal and subterminal α-linked dGal were as active or less active than dGal. dGalβ1 → 3dGlcNAcβ1 → 3dGalβ1 → 4dGlc (lacto-N-tetraose) and dGalβ1 → 3dGlcNAcβ1 → 3dGal-β1-O-(CH₂)₈COOCH₃ were equally active and 1.5 times as potent as dGalβ1 → 3dGlcNAc whereas dGalβ1 → 3dGlcNAcβ1 → 6dGal was only 40% as potent as dGalβ1 → 3dGlcNAc suggesting that a third sugar may be part of the determinant. Substitution of dGalβ1 → 3dGlcNAcβ1 → 3dGalβ1 → 4dGlc on the subterminal dGlcNAc by lFucα1 → 4 in lacto-N-fucopentaose II reduced activity fourfold; if the nonreducing dGal is substituted by lFucα1 → 3 as in lacto-N-fucopentaose I its activity is almost completely abolished. This suggests that a terminal nonreducing dGal as well as subterminal dGlcNAc are contributing to binding. The β → 3 linkage of the terminal dGal to the subterminal amino sugar is significant since dGalβ1 → 4dGlcNAc is a poorer inhibitor. Although the available data suggest that the combining site of the lectin Bauhinia purpurea alba may be most complementary to the structure dGalβ1 → 3dGalNAcβ1 → 3dGal, several other possibilities remain to be tested when suitable oligosaccharides become available.     

Differential binding characteristics and applications of DGal beta 1----3DGalNAc specific lectins

The binding properties of Arachis hypogaea (PNA), Bauhinia purpurea alba (BPL), Maclura pomifera ( MPL ) and Sophora japonica (SJL) lectins were studied by quantitative precipitin and precipitin inhibition assays, demonstrating them to be most specific for DGal beta 1---- 3DGalNAc residues. Additionally, each lectin had its own binding characteristic such as different binding activities to DGal beta 1---- 4DGlcNAc or DGal beta 1---- 3DGlcNAc beta 1----linked oligosaccharides, and/or DGalNAc alpha 1----linked to the Ser or Thr of the protein moiety. These differential binding characteristics can be used for investigating fine differences of the carbohydrate structure of the glycoconjugates, especially those having DGal beta 1---- 3DGalNAc residues as terminal non-reducing ends.     

Immunochemical studies on the combining site of the d-galactose/N-acetyl-d-galactosamine specific lectin from Erythrina cristagalli seeds

The combining site of the Erythrina cristagalli lectin was studied by quantitative precipitin and precipitin inhibition assays. The lectin precipitated best with two fractions of a precursor human ovarian cyst blood group substance with I and i activities. A₁, A₂, B, H, Le^a, and Le^b blood group substances precipitated poorly to moderately and substances of the same blood group activity precipitated to varying extents. These differences are attributable to heterogeneity resulting from incomplete biosynthesis of carbohydrate chains. Specific precipitates with the poorly reactive blood group substances were found to be more soluble than those reacting strongly. Precipitation was minimally affected by EDTA or divalent cations. Among the monosaccharides and glycosides tested for inhibition of precipitation, p-nitrophenyl βdGal was most active and was 10 times more active than methyl βdGal, indicating involvement of hydrophobic contacts in site specificity. Methyl αdGalNAc, p-nitrophenyl αdGalNAc, methyl αdGal, N-acetyl-d-galactosamine, p-nitrophenyl αdGal, methyl βdGal, and p-nitrophenyl βdGalNAc were progressively less active than p-nitrophenyl βdGal. The best disaccharide inhibitor dGalβ1 → 4dGlcNAc was 7.5 times more potent than p-nitrophenyl βdGal. A tetraantennary and triantennary oligosaccharide containing four and three dGalβ1 → 4dGlcNAcβ1 → branches, respectively, were, because of cooperative binding effects, 1.6 and 2.5 times more active than the bi- and monoantennary oligosaccharides, respectively. dGalβ1 → 4dGlcNAcβ1 → 6dGal and dGalβ1 → 4dGlcNAcβ1 → 2dMan had the same activity, being 1.5 times more active than dGalβ1 → 4dGlcNAc, which was 2.6 and 8.5 times more active than dGalβ1 → 3dGlcNAc and dGalβ1 → 3dGlc, respectively. Substitutions by N-acetyl-d-galactos-amine or l-fucose on the d-galactose of inhibitory compounds blocked activity. These results suggest that a hydrophobic interaction with the subterminal sugar is important in the binding and that the specificity of the lectin combining site involves a terminal dGalβ1 → 4dGlcNAc and the β linkage of a third sugar.     

Immunochemical studies on the reactivities and combining sites of the d-galactopyranose- and 2-acetamido-2-deoxy-d-galactopyranose-specific lectin purified from Sophora japonica seeds

Sophora japonica lectin agglutinates human B erythrocytes strongly and A₁ erythrocytes weakly. Bivalent metal ions such as Ca²⁺, Mn²⁺, or Mg²⁺ were shown to be essential for hemagglutinating and precipitating activities. At optimal concentrations of bivalent metal ions, hemagglutinating activity was highest between pH 8.5 and 9.0 and decreased sharply below pH 8.5, whereas precipitating capacity was maximal between pH 6.7 and 9.5. The combining site of the S. japonica lectin was explored by quantitative precipitin and precipitin inhibition assays. This lectin showed substantial differences in precipitation with several blood group B substances ascribable to heterogeneity resulting from incomplete biosynthesis of their carbohydrate side chains. The lectin precipitated moderately well with A₁ substance and precursor blood group I fractions (OG). It precipitated weakly or not at all with A₂, H, or Le^a substances. In inhibition assays, glycosides of dGalNAc were about five to six times better than those of dGal; dGalNAc itself was about six times better than dGal. Nitrophenyl glycosides were all substantially better than the methyl glycosides, indicating a hydrophobic contribution to the site subterminal to the nonreducing moiety. Although nitrophenyl β-glycosides were much better than the corresponding α-glycosides, the methyl α-and βDGalNAcp were equal in activity as were methyl α- and βDGalp. Among the oligosaccharides tested, the β-linked N-tosyl-l-serine glycoside of dGalβ1 → 3dGalNAc was best and was as active as p-nitrophenyl βDGalNAcp, whereas dGalβ1 → 3dGalNAc α-N-tosyl serine and the nitrophenyl and phenyl α-glycosides of dGalβ1 → 3dGalNAc were much less active, suggesting that the hydrophobic moiety and/or a subterminal dGalNAc β-linked and substituted on carbon 3 play an important role in binding and that a β-linked glycoside of dGalβ1 → 3dGalNAc may be an essential requirement for binding. The results of inhibition studies with other oligosaccharides indicate that a subterminal dGlcNAc substituted on carbon 3 or 4 by dGalβ may contribute somewhat to binding and that whether the dGlcNAc is linked β1 → 3 or β1 → 6 to a third sugar does not contribute to or interfere with binding. The β1 → 3 linkage of the terminal dGal to the subterminal amino sugar is significant since dGalβ1 → 4dGlcNAc was one-half as active as the corresponding β1 → 3-linked compound and the subterminal sugar must be unsubstituted for optimal binding. N-Acetyllactosamine was 50% more active than lactose, indicating that the subterminal N-acetamido group was also contributing significantly to binding. A variety of other sugars, glycosides, and oligosaccharides showed little or not activity. From the oligosaccharides available, the combining size of this lectin would appear to be least as large a β-linked disaccharide and most complementary to dGalβ1 → 3dGalNAc β-linked to tosyl-l-serine the most active compound tested.     

Immunochemical studies on the specificity of the peanut (Arachis hypogaea) agglutinin.

The specificity of purified, peanut agglutinin has been studied immunochemically by quantitative precipitin and inhibition assays. The lectin showed substantial differences in precipitating with blood-group substances of the same specificity. Of the B substances tested, horse 4 25% completely precipitated the lectin, Beach phenol insoluble failed to interact, and PM phenol insoluble gave an intermediate reaction. The lectin did not precipitate with A1 substances, with hog gastric mucin A + H substance, or with A2 substance WG phenol insoluble. Another A2 substance, cyst 14 phenol insoluble, precipitated approximately 2/3 of the lectin. Of the H substances, Tighe phenol insoluble was inactive, JS phenol insoluble precipitated poorly, and morgan standard H precipitated about 80% of the lectin. However, first stage of Smith degradation, as well as Pl fractions obtained by mild acid hydrolysis of blood-group substances, gave products which precipitated strongly. The lectin was also completely precipitated by all precursor blood-group substances, as well as by cows 21 and 26, all having strong I-Ma, I-Ort, I-Step, and I-Da activities. Cow 18, which does not possess significant blood-group I activity, precipitated very slightly. Fractions of blood-group substances N-1 (Lea) and Tij (B) obtained by precipitation from 90 percent phenol at higher concentrations of ethanol interacted better with peanut agglutinin. These differences in activity are ascribable to a heterogeneity resulting from incomplete biosynthesis of carbohydrate side-chains of blood-group substances, particularly resulting in variations in the numbers of DGalbeta1 leads to 3DGalNAc or DGalbeta1 leads to 4DGlcNAc determinants. The agglutinin reacted with the hydatid cyst P1 glycoprotein, as well as with the previously studied antifreeze and sialic acid-free alpha1 acid glycoproteins, but not with pneumococcus type XIV polysaccharide. Inhibition of precipitation showed the lectin to be most specific for the disaccharide DGalbeta1 leads to 3DGalNAc, which is 14, 55, and 90 times as active as DGalbeta1 leads to 4DGlcNAc, DGal, and DGalbeta1 leads to 3DGlcNAc, respectively. DGalbeta1 leads to 3N-acetyl-D-galactosaminitol has approximately 1/25th the activity of DGalbeta1 leads to 3DGalNAc. Substitutions of DGlcNAc or LFuc on the DGal of active inhibitors completely blocked the activity, in line with the assumption that the combining site of the peanut lectin is a partial cavity. The oligosaccharides DGalbeta1 leads to 4DGlcNAcbeta1 leads to 6-hexane-1,2,4,5,6-pentol(s) and DGalbeta1 leads to 3[DGalbeta1 leads to 4DGlcNAcbeta1 leads to 6]N-acetyl-D-galactosaminitol showed the same inhibitory activity as DGalbeta1 leads to 4DGlcNAc, suggesting that the combining site of the peanut agglutinin may not be complementary to more than a disaccharide...     

Binding of synthetic sulfated ligands by human splenic galectin 1, a β-galactoside-binding lectin

The carbohydrate-binding site of galectin 1, a vertebrate β-galactoside-binding lectin, has a pronounced specificity for the βGal(1→3)- and βGal(1→4)GlcNAc sequences. The binding inhibition study reported herein was carried out to determine whether sulfation of saccharides would influence their binding by galectin 1. The presence of 6′-OSO3- on LacNAc greatly reduces the inhibitory potency relative to LacNAc. 3′-OSO3-LacNAc, 3′-OSO3-Galβ(1→3)GlcNAcβ1-OBzl and 3-OSO3-Galβ1-OMe are more potent inhibitors than the non-sulfated parent compounds. Surprisingly, 2′-OSO3-LacNAc showed over 40 fold less inhibitory potency relative to LacNAc. Ovarian carcinoma A121 cells were shown to synthesize sulfated macromolecules that bind to galectin 1. Modulation in vivo of saccharide sulfation may lead to modulation of galectin 1 interaction with glycoconjugates; hence, sulfation could play a role in modulating lectin functions.     

Interaction of mannose-containing oligosaccharides with the fimbrial lectin of Escherichia coli

The sugar specificity of Escherichia coli 346 and of the type-1 fimbriae isolated from this organism has been studied by quantitative inhibition of the agglutination of mannan-containing yeast cells. The best inhibitors of the agglutination by the bacteria were the oligosaccharides Manα1→6[Manα1→3]Manα1→6[Manα1→2Manα1→3]ManαOMe, Manα1→6[Manα1→3]Manα1→6[Manα1→3]ManαOMe and Manα1→3Manβ1→4GlcNAc, and the aromatic glycoside p-nitrophenyl α-d-mannoside, all of which were 20–30 times more inhibitory than methyl α-d-mannoside. The disaccharides Manα1→3Man, Manα1→2Man and Manα1→6Man, the tetrasaccharide Manα1→2Manα1→3Manβ1→4GlcNAc and the pentasaccharide Manα1→2Manα1→2Manα1→3Manβ1→4GlcNAc, were all poor inhibitors. A very good correlation was found between the relative inhibitory activity of the different sugars tested with intact bacteria and with the isolated fimbriae. Our findings show that the combining site of the E. coli lectin is an extended one, corresponding to the size of a trisaccharide, that it contains a hydrophobic region, and that it is in the form of a pocket on the surface of the lectin. The combining site fits best the structures found in short oli gomannosidic chains present in N-glycosidically linked glycoproteins.     

A method of selective histochemical analysis of sialoglycoproteins using lectins from elder (Sambucus nigra L.)]

Good potentialities in application of elderberry (Sambucus nigra L.) bark lectin for selective histochemical identification of sialylated glycoconjugates has been demonstrated using lectin-peroxidase technique. In order to omit this lectin binding to D-galactose and N-acetyl-D-galactosamine residues, preincubation of tissue sections with non-marked PNA and SBA (or other lectins with similar carbohydrate specificity) is proposed. By means of neuraminidase digestion it has been ascertained, that oligosaccharide chains of secretory glycopolymers, synthesised in ovine submandibular gland mucocytes, contain DGal and DGalNAc residues penultimate to terminal sialic acids.     

The amino acid sequence of toxin V from Anemonia sulcata

Preparations of the β-galactoside-binding lectin of bovine heart have been shown to stimulate $\text{in vitro}$ the sialylation of the oligosaccharide Ga1β1→4G1cNAc and asialo-α₁-acid glycoprotein by bovine colostrum β-D-galactoside α2→6 sialyltransferase. Kinetic data revealed that in the presence of lectin the K_m values for Ga1β1→4G1cNAc and CMP-NeuAc were reduced from 25.0 to 11.6 mM and from 0.42 to 0.19 mM respectively, but the K_m for asialo-α₁-acid glycoprotein and the V_max values for all three substrates were little affected. Stimulation by the lectin was partially inhibited by Fucα1→2Ga1β1→4G1cNAc. This, together with the effects of certain plant lectins, suggests that the stimulation of sialytransferase may be mediated through the carbohydrate-binding properties of the lectin.     

Preparation, characterization, and biological evaluation of 6(I),6(IV)-di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose

6(I),6(IV)-Di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose (βCD) {6(I),6(IV)-di-O-[α-l-Fuc-(1→6)-β-d-GlcNAc]-βCD (5)} and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-βCD {6-O-[α-l-Fuc-(1→6)-β-d-GlcNAc]-βCD (6)} were chemically synthesized using the corresponding authentic compounds, bis(2,3-di-O-acetyl)-pentakis(2,3,6-tri-O-acetyl)-βCD as the glycosyl acceptor and 2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(1→6)-3,4-di-O-acetyl-2-deoxy-2-(2,2,2-trichloroethoxycarbonylamino)-d-glucopyranosyl trichloroacetimidate as the fuco-glucosaminyl donor. NMR confirmed that α-l-Fuc-(1→6)-d-GlcNAc was bonded by β-linking to the βCD ring. To evaluate biological efficiency, the biological activities of the new branched βCDs were examined. The cell detachment activity of 5 was lower than that of 6 in real-time cell sensing (RT-CES) assay, indicating that 5 has lower toxicity. In SPR analysis, 5 had a higher special binding with AAL, a fucose-recognizing lectin. These results suggest that 5 could be an efficient drug carrier directed at cells expressing fucose-binding proteins.