白术多糖的分离纯化与结构表征

采用UV, IR, NMR, GC-MS, 高碘酸氧化和Smith降解等物理化学方法对从白术根茎提取的白术多糖的纯度、理化性质和结构进行了表征. 以中药白术的根茎为原料, 通过热水(80 ℃)浸提和乙醇醇沉得到粗多糖, 再经DEAE-52阴离子交换柱层析分离和Sephadex G-200凝胶柱层析纯化, 得到一种水溶性的白术多糖(WAM). 经高效液相色谱(HPLC)分析, 多糖WAM是分子量约为3263的均一多糖. GC分析表明, WAM是由葡萄糖和半乳糖以摩尔比3.01:1构成的杂多糖. 甲基化分析、高碘酸氧化、Smith降解、部分酸水解、NMR和IR等分析结果表明, WAM具有多分支结构, 主链由β-D-1→3和β-D-1→3,6吡喃葡萄糖构成, 每个重复单元具有一个支链, 支链由β-D-半乳糖构成, 连接在主链葡萄糖的6位碳原子上.     

玉米芯水溶性多糖的分离纯化和抗凝血活性研究

从玉米芯中提取到水提水溶性粗多糖,通过乙醇分级、冻融、凝胶过滤层析,生物测定导向等手段,分离到一种能延长体外凝血时间,而且具有外源抗凝血功能的多糖CCⅢ.CCⅢ对活化部分凝血酶原时间(APTT)无显著影响,但可显著延长体外抗凝血时间(PT).将CCⅢ纯化,经糖组成分析、甲基化、高碘酸氧化、Smith降解和GC-MS分析,确定该多糖结构为:β-(1→4)Glc,(1→3)Xyl构成主链,Glc在6-O处有分枝.平均每10个糖残基有1个分枝,支链由β-(1→3)Xyl,(1→3)Glc构成.     

巴戟天中一种多糖的分离与结构表征

以巴戟天的根为原料, 经热水浸提、Sevag法除蛋白、乙醇沉淀和DEAE-Sepharose CL-6B离子交换柱层析, 得到一种水溶性的巴戟天多糖(MOPI-3). 通过UV、IR、NMR、GC-MS、高碘酸氧化、Smith降解和甲基化等物理化学方法对MOPI-3的纯度、理化性质和组成结构进行表征. 结果表明, MOPI-3分子量为36061, 是一种由阿拉伯糖、半乳糖和葡萄糖组成的杂多糖, 以α-1,3-吡喃葡萄糖和α-1,4-吡喃半乳糖为主链, 平均每5个葡萄糖连接一个半乳糖, 每个重复单元具有一个支链, 支链由3个呋喃阿拉伯糖以α-1,3-键型组成, 连接在主链葡萄糖的6位碳上, MOPI-3含有乙酰基, 连接在主链半乳糖的2位碳原子上.     

玉米芯酸提水溶性多糖CCCP的分离纯化和结构研究

玉米芯用PH=3的HCl煮提得到酸提水溶性粗多糖．该粗多糖组成为Glc，Xyl，Gal，经乙醇分级和Sepharose CL-6B柱层析纯化，得到多糖CCCP．经Sephadex A-25柱层析、比旋光度测定、醋酸纤维薄膜电泳等方法鉴定CCCP为均一多糖．经唾液淀粉酶解、纤维素酶解、部分酸水解、高碘酸氧化、Smith降解、甲基化分析及IR，GC和GC／MS等方法分析表明：CCCP为少分枝结构；主链由吡喃型(1→3)Xyl构成，在O(4)处有分枝；支链主要由(1→4)Glc构成，在O(6)处有分枝，支链还存在1→3，1→6键型连接的Glc，Gal；末端基为Xyl，Glc，Gal．     

榆耳水溶性多糖GIA的结构分析

用6%尿素从榆耳(Gloeostereuminsarnatum)子实体中提取出水溶性粗多糖,经乙醇分级及SeoharoseCL-6B制备柱收集得到组分GIA.经SephadexG-75、DEAE-阴离子交换纤维素和HPLC验证,GIA分子量及极性为均一组分.气相色谱(GC)分析表明,其单糖组成为Xyl,Gal和Glc.HPLC测得平均分子量为18000.经IR、GC、部分酸水解、高碘酸氧化、Smith降解、¹³CNMR、甲基化分析及其产物的GC-MS联机分析表明,GIA为少分支结构,主要由α型糖苷键构成,少部分由β型糖苷键构成;主体结构由Gal和Glc组成,其中主要为Gal1→6,还有Glc1→6;Gal1→6和Glc1→6在3-O处有分支;平均每10个己糖残基有2个分支;GIA的支链部分由Gal1→3和Glc1→3构成;末端残基为Xyl,Gal,Glc.     

榆耳水溶性多糖的结构特征

用3%三氯醋酸从榆耳子实体中提取出水溶性粗多糖,经乙醇分级、SepharoseCL6B纯化得到单一组分GIA.SepharoseCL6B柱层析测得GIA的相对分子质量为1 26×105.GC分析表明GIA由Man和Glc两种单糖构成,其物质的量比为1 42∶1.多糖GIA经部分酸水解、高碘酸氧化、Smith降解和甲基化分析其结构主要为β(1→3)Man和β(1→3)Glc,且在6～0处构成分枝结构,平均每11个己糖残基有2个分枝,多糖GIA的支链部分由(1→4)Glc构成,末端残基为Man,Glc.     

松木层孔菌多糖PEP的结构及活性研究

从松木层孔菌发酵菌丝体中分离制备碱提水溶性多糖(PEP).高效液相色谱分析表明,PEP为单一级分,相对分子质量约为1.6×104.GC分析PEP的单糖组成为甘露糖、半乳糖和葡萄糖,其物质的量比为3.11∶1.32∶0.54.PEP经部分酸水解、高碘酸氧化、Smith降解和甲基化分析,其结构主要为β-(1→2)Man且在6-0处构成分枝结构,PEP的支链部分由(1→4)-Man,(1→6)-Gal构成,末端残基为Gal和Glc.初步考察,PEP对小鼠离体淋巴细胞有较显著的促增殖作用.     

鬼臼葡聚糖的化学结构

从植物鬼臼根的沸水提取液中分离出一个水溶性多糖EPS。它是由单一葡萄糖残基构成的葡萄糖, 分子量约为1.6×10^4。经酸全水解, 甲基化反应, 高碘酸氧化, Smith降解, KI-I~2反应, IR, ^1H NMR和^1^3C NMR分析, 证明其化学结构为1,4-葡萄糖残基为主链, 并在6-O位有侧链的葡聚糖。     

碱提猴头发酵菌丝体水溶性多糖HPP的结构确定

从猴头发酵菌丝体水提后残渣中用碱提出了水溶性粗多糖,对其分级纯化得到纯样HPP,SepharoseCL-6B柱层析测得其相对分子质量约为6 53×104,G C 分析表明,其单糖组成为Glc;经部分酸水解、高碘酸氧化、Smith降解和甲基化分析确定此多糖为多分枝结构,其中(1→6)Glc构成主链的核心结构;分支点为O-3;支链部分由(1→3)Glc构成,并连接一端基Glc.     

沙棘果皮水溶性多糖H_n的结构研究

沙棘果皮水溶性多糖经酸性乙醇分级和DEAE -SephadexA - 2 5柱层析纯化 ,得到多糖Hn.经SepharoseCL - 4B柱层析、玻璃纤维纸电泳、比旋光度测定等方法鉴定Hn 为均一多糖 .经唾液淀粉酶解、部分酸水解、高碘酸氧化、Smith降解、甲基化分析及IR ,1 3C -NMR ,GC和GC -MS等方法 ,确定其基本结构中主链由 1→ 4Glc基、1→ 6Man基和 1→ 6Gal基构成 .三者摩尔比为nGlc∶nMan∶nGal=3∶1 .5∶1 ,分支点在 3—O处 ,分支率为 43% ,侧链由 1→ 6Gal基、1→ 4Glc基、末端Glc或末端Ara基构成 .     

Purification,characterization, and modification of T lymphocyte-stimulating polysaccharide from spores of Ganoderma lucidum

The hot-water extract of the spores of Ganoderma lucidum was shown to have a stimulating effect on concanavalin A-induced mitogenic activity of T lymphocytes. Bioassay-guided separation led to the isolation of a polysaccharide with potent T lymphocyte-stimulating activity by ethanol fractionation, anion-exchange, and size-exclusion chromatography. Based on the composition and methylation analyses, periodate oxidation, Smith degradation, and NMR spectroscopy, the native polysaccharide was shown to be a beta-D-(1-->3)-glucan with branches of terminal glucosyl residues substituted at C-6 of the glucose residues in the main chain. The branching ratio is approximately 20%. A series of sulfated or carboxymethylated derivatives were prepared and their structural features were elucidated by chemical and spectral analyses. The solution conformation and T lymphocyte proliferation effect of the glucans before and after derivatization were compared and discussed. The data obtained indicate that the introduction of ionic groups would significantly affect the original conformation of the native glucan in aqueous solution and further affect T lymphocyte-stimulating activity. The triple-helical structure of the glucans, the nature of the ionic groups, and the density of negative charge were considered to be closely related to this activity.     

菌类多糖链构象及其表征方法研究进展 （专题报道）

 概述了菌类多糖在溶液中链构象及其表征方法的研究进展.主要报道从各种真菌（香菇、茯苓、灵芝、木耳、黄单胞菌、裂褶菌等）中提取的多糖在溶液中的分子量、分子形态和尺寸,即链构象.同时介绍多糖链构象对生物活性的影响,并且指出多糖刚性链带电基团及适量分子量有利于促进它与免疫细胞上受体结合,从而抑制肿瘤细胞增殖.由此表明,多糖链构象的研究对弄清其生物功能和推动生命科学发展十分重要.多糖在溶液中主要以无规线团、双螺旋、三螺旋、蠕虫状、棒状链以及聚集体构象存在,它取决于单糖组成、糖苷键、支链结构以及分子内和分子间作用力.测定链构象的方法主要包括光散射、黏度、显微技术（透射电镜,扫描电镜以及原子力显微镜）、微量热法和小角X-射线散射等.此外,介绍了多糖溶液理论以及计算链构象参数的表达式.     

灵芝富碘实验中多糖含量变化的探讨

阐述了ＴＷ灵芝在液体深层培养中，进行富集碘实验过程菌丝体多糖含量的变化．实验表明，在ＴＷ灵芝液体培养中添加１０００×１０－６～８０００×１０－６浓度的碘化钾，菌丝体多糖含量为０．９２％～１．５８％．     

Conformation and Hydrolytic Stability of Polysaccharide from Xanthomonas campestris

Xanthomonas campestris polysaccharide in the solid state is stable to 225°C in air and 250°C in inert atmosphere. In solution, even at moderate temperatures, the polymer undergoes hydrolytic degradation via the glycosidic linkages, and occurrence of main-chain scission results in lower solution viscosity. In solution, the polymer can exist in ordered and disordered conformations. In distilled water at temperatures ≤ 50°C, the polymer exists in the disordered conformation. In the presence of salt, acid, or base the polymer exists in the ordered conformation. In the ordered conformation the polymer exhibits a far greater hydrolytic stability. The higher stability of the ordered conformation is especially demonstrated when the polymer is aged in acid or base solutions. Contrary to the expected lower stability of the glycosidic linkages in acid or base than in water, Xanthomonas campestris polysaccharide shows higher stability in these media.     

Application of 2,3-naphthalenediamine in labeling natural carbohydrates for capillary electrophoresis

Neutral and acidic monosaccharide components in Ganoderma lucidum polysaccharide are readily labeled with 2,3-naphthalenediamine, and the resulting saccharide-naphthimidazole (NAIM) derivatives are quantified by capillary electrophoresis (CE) in borate buffer. Using sulfated-α-cyclodextrin as the chiral selector, enantiomers of monosaccharide-NAIMs are resolved on CE in phosphate buffer, allowing a simultaneous determination of the absolute configuration and sugar composition in the mucilage polysaccharide of a medicinal herb Dendrobium huoshanense. Together with the specific enzymatic reactions of various glycoside hydrolases on the NAIM derivatives of glycans, the structures of natural glycans can be deduced from the digestion products identified by CE analysis. Though heparin dissachrides could be successfully derived with the NAIM-labeling method, the heparin derivatives with the same degree of sulfation could not be separated by CE.     

菌类多糖链构象及其表征方法研究进展

概述了菌类多糖在溶液中链构象及其表征方法的研究进展.主要报道从各种真菌(香菇、茯苓、灵芝、木耳、黄单胞菌、裂褶菌等)中提取的多糖在溶液中的分子量、分子形态和尺寸,即链构象.同时介绍多糖链构象对生物活性的影响,并且指出多糖刚性链带电基团及适量分子量有利于促进它与免疫细胞上受体结合,从而抑制肿瘤细胞增殖.由此表明,多糖链构象的研究对弄清其生物功能和推动生命科学发展十分重要.多糖在溶液中主要以无规线团、双螺旋、三螺旋、蠕虫状、棒状链以及聚集体构象存在,它取决于单糖组成、糖苷键、支链结构以及分子内和分子间作用力.测定链构象的方法主要包括光散射、黏度、显微技术(透射电镜,扫描电镜以及原子力显微镜)、微量热法和小角X-射线散射等.此外,介绍了多糖溶液理论以及计算链构象参数的表达式.     

天然聚多糖的溶解机理及溶液性质

21世纪"绿色"化学已成为各国科学界和工业界研究与开发的方向.天然高分子中纤维素、甲壳素等聚多糖来源丰富,是重要的可再生资源,也是未来主要的化工原料之一.由于大量的分子内和分子间氢键,它们的溶解长期以来都是非常棘手的问题.另一方面,聚多糖的结构非常复杂,只有弄清楚其链构象和溶液性质,才可能进行合理的分子设计,实现其更好的应用.本文简要介绍了本课题组用碱/尿素水体系低温溶解纤维素和甲壳素等天然高分子的机理和溶液中分子链构象,以及活性多糖在水溶液中的链构象和溶液性质的研究进展.     

Molecular dynamics simulations of the Salmonella typhi Vi antigenic polysaccharide and effects of the introduction of a zwitterionic motif

A series of hexasaccharides corresponding to the Vi capsular polysaccharide, a polymer of α-(1→4)-galacturonic acid, and analogs containing a zwitterionic motif with various degrees of acetylation at positions 3 have been modeled. When submitted to molecular dynamics simulations in a water box, all the structures visited only two quite restricted regions of the φ/ψ conformational space both corresponding to extended geometries without any tendency towards supercoiling. The most stable conformation showed a clockwise helix arrangement of substituents on the molecular surface whereas the opposite arrangement was observed for the other conformation. The flexibility of the system and the hydrophobic character of the molecular surface are modulated by the 3-O-acetyl groups that confer rigidity to the system. In the zwitterionic analogs, the introduction of positive charges in the place of the acetamido groups alters the hydrophobicity that can be regained by methylation of the amino groups. The needed molecular flexibility can be obtained by the complete deacetylation at positions 3.     

Deconvoluted Fourier-transform LNT-IR study of coordination copper(II) compounds with dextran derivatives

Deconvoluted Fourier-transform IR spectra, recorded at room and liquid nitrogen temperature, of polysaccharide dextran and its coordination compounds with the copper(II) ion were analyzed in order to find the most specific spectral peculiarities. This allows one to obtain information about the structure and conformation of these polymer compounds. Different influences on the system of intra-and intermolecular interactions were exhibited by analogs recrystallized from D₂O. The changes in intensity and width of the IR bands in the region 1450–1050 cm⁻¹ were related to changes in conformation and short-range interactions of the dextran. In the synthesized copper(II)-dextran complexes, the presence of water molecules was confirmed. The results of the FTIR spectroscopy study allowed one to suggest a predominant crystalline form of the copper(II)-dextran complexes. The text was submitted by the authors in English.     

MALDI-TOF MS analysis of native and permethylated or benzimidazole-derivatized polysaccharides

MALDI-TOF MS provides rapid and sensitive analyses of larger biomolecules. However, MS analyses of polysaccharide have been reported to have lower sensitivity compared to peptides and proteins. Here, we investigated some polysaccharides chemically derivatized by permethylation and ortho-phenylene diamine (OPD) tagging. Methylated glycan is obviously able to improve the sensitivity for mass spectrometry detection. Oxidative condensation by UV-activation tagging to saccharides by OPD and peptide-OPD also improve the sensitivity of MALDI-TOF MS analyses. Polysaccharides including dextran, glucomannan, arabinoxylan, arabinogalactan and beta-1,3-glucan, isolated from nutritional supplements of Ganoderma lucidum and Saccharomyces pastorianus were measured using MALDI-TOF MS with 2,5-dihydroxybenzoic acid (2,5-DHB) as the matrix. These glycans were also derivatized to methylated and benzimidazole-tagged glycans by chemical transformation for molecular weight analysis. The derivatized polysaccharides showed excellent MALDI-TOF MS signal enhancement in the molecular weight range from 1 to 5 kDa. Here, we demonstrate an efficient method to give glycan-benzimidazole (glycan-BIM) derivatives for polysaccharide determination in MALDI-TOF MS. Therefore, permethylated or benzimidazole-derivatized polysaccharides provide a new option for polysaccharide analysis using MALDI-TOF MS.