寡糖又称为低聚糖,是由2至10个相同或不同的单糖单位通过糖苷键连接起来形成的直链或含分支链的糖类化合物。尽管寡糖和单糖在物理及化学性质上相似,它们都易溶于水,并且很多低聚糖具有甜味,可被费林溶液氧化;不同之处在于它们在水解后能产生十个以下的单糖分子。
根据单糖单位的数量,寡糖可分为双糖、三糖、四糖和五糖等。构成寡糖的单糖可以相同也可以不同,与一般的糖苷不同的是,它们的配基也是糖。例如,蔗糖为典型的双糖,棉子糖为三糖,水苏糖为四糖,毛蕊花糖为五糖。
寡糖易溶于水或其他极性溶剂,并且分为还原性和非还原性两类,在生物体内从单糖逐步合成或由多糖降解产生。在植物细胞壁中的结构多糖,在病原体入侵时会分解成为具有生物活性的碎片,被称为寡糖素(oligosaccharin),对植物起保护和调节作用。
最常见的三糖是棉子糖,广泛存在于甜菜和棉籽中。制造蔗糖过程中产生的糖浆是提取棉子糖的良好原料。棉子糖水解后会得到半乳糖、葡萄糖及果糖各一分子。棉子糖是非还原性糖,其分子内的葡萄糖与果糖通过半缩醛羟基相连,而半乳糖则与葡萄糖之间形成1,6-糖苷键,结合顺序如下:半乳糖–(1->6)–葡萄糖–(1->2)–果糖。
水苏糖是自然界中重要的四糖之一,在棉子糖分子中通过6→1糖苷键在半乳糖的基础上连接一个半乳糖形成。类似地,还可以依次添加α-D-半乳糖生成五糖、六糖和七糖等同系物。这些水苏糖及其同系物都是植物的抗冻物质。
中文名称 | 英文名称 | CAS号 | 化学式 | 结构式图片 |
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N-乙酰胞壁酸 | (2R)-2-{[(2R,3R,4R,5R)-2-acetamido-4,5,6-trihydroxy-1-oxohexan-3-yl]oxy}propanoic acid | 10597-89-4 | C11H19NO8 |
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N-乙酰-D-乳糖胺 | N-acetyllactosamine | 32181-59-2 | C14H25NO11 |
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N,N’,N’’-三乙酰壳三糖 | N,N'-diacetylchitotriose | 38864-21-0 | C24H41N3O16 |
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N,N’,N,N’’’,N’’’’,N’’’’’-六乙酰壳六糖 | hexa-N-acetylchitohexaose | 38854-46-5 | C48H80N6O31 |
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N,N',N,N''',N-五乙酰壳五糖 | N,N',N'',N''',N''''-Pentaacetylchitinpentaose | 36467-68-2 | C40H67N5O26 |
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D-甘露(型)庚酮糖 | DL-<i>manno</i>-[2]Heptulose | 3615-44-9 | C7H14O7 |
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D-水苏糖 | stachyose | 470-55-3 | C24H42O21 |
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D-(+)-纤维四糖 | cellotetraose | 38819-01-1 | C24H42O21 |
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D-(+)-纤维三糖 | cellotriose | 33404-34-1 | C18H32O16 |
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D(+)松三糖,水合 | Melezitose dihydrate | 10030-67-8 | C18H36O18 |
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D(+)-海藻糖二水合物 | Trehalose dihydrate | 6138-23-4 | C12H26O13 |
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D(+)-五水棉子糖 | D(+)-Raffinose pentahydrate | 17629-30-0 | C18H42O21 |
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B-D-龙胆 | Isomaltotriose | 3371-50-4 | C18H32O16 |
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6-alpha-D-吡喃葡萄糖基麦芽三糖 | 6-alpha-D-Glucopyranosyl maltotriose | 34336-93-1 | C24H42O21 |
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6'-半乳糖基乳糖 | O4-(O6-β-D-Glucopyranosyl-β-D-glucopyranosyl)-D-glucose | 7485-51-0 | C18H32O16 |
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4-硝基苯基-β-D-纤维三糖苷 | 4-Nitrophenyl beta-D-cellotrioside | 106927-48-4 | C24H35NO18 |
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4-硝基苯基-Β-D-乳糖苷 | p-nitrophenyl β-lactoside | 4419-94-7 | C18H25NO13 |
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4-硝基苯基-Β-D-N,N’ N’-三乙酰壳三糖糖苷 | 4-Nitrophenyl beta-D-N,N',N''-triacetylchitotriose | 7699-38-9 | C30H44N4O18 |
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4-硝基苯基 4-O-(2,3,4,6-O-四乙酰基-beta-D-吡喃半乳糖基)-2,3,6-O-三乙酰基-beta-D-硫代吡喃葡萄糖苷 | 4-nitrophenyl 2,3,6,2',3',4',6'-hepta-O-acetyl-1-thio-β-lactoside | 27894-81-1 | C32H39NO19S |
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4-甲基伞形酮-Β-D-纤维三糖苷 | 7-[5-[3,4-Dihydroxy-6-(hydroxymethyl)-5-[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]oxy-3,4-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-4-methylchromen-2-one | 84325-18-8 | C28H38O18 |
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4-甲基伞形酮 N,N',N''-三乙酰基-beta-壳丙糖苷 | 4-methylumbelliferyl β-D-N,N′,N″-triacetylchitotrioside | 53643-13-3 | C34H47N3O18 |
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4-O-alpha-D-吡喃半乳糖基-D-半乳糖 | <i>O</i><sup>4</sup>-α-D-Galactopyranosyl-D-galactose | 13117-26-5 | C12H22O11 |
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4-O-(2,3,4,6-四-O-乙酰基)-β-D-吡喃(型)葡糖基-D-吡喃(型)葡糖四乙酸酯 | D-cellobiose octaacetate | 3616-19-1 | C28H38O19 |
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3A-氨基-3A-脱氧-(2AS,3AS)-β-环糊精水合物 | 3<sup>A</sup>-amino-3<sup>A</sup>-deoxy-altro-β-cyclodextrin | 117194-77-1 | C42H71NO34 |
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3-路易斯寡糖-X四糖 | Sialyl-Lewis X | 98603-84-0 | C31H52N2O23 |
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3-O-己糖吡喃糖苷吡喃己糖 | 3-O-α-D-mannopyranosyl-D-mannopyranose | 23745-85-9 | C12H22O11 |
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3-O-(A-D-吡喃甘露糖苷)-A-D-吡喃甘露糖苷-4-硝基苯酯 | p-nitrophenyl 3-O-α-D-mannopyranosyl-α-D-mannopyranoside | 26255-70-9 | C18H25NO13 |
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3,6-双邻(alpha-d-呋喃鼠李糖)-d-呋喃鼠李糖 | 3,6-Di-O-(alpha-D-mannopyranosyl)-D-mannopyrannose | 121123-33-9 | C18H32O16 |
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2-氯-4-硝基苯基-β-D-麦芽三糖糖苷 | 2-Chloro-4-nitrophenyl-beta-D-maltotrioside | 165522-16-7 | C24H34ClNO18 |
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2-乙酰氨基-2-脱氧-6-o-(beta-d-氟代半乳糖)-d-吡喃葡萄糖 | N-Acetyl-allolactosamin | 50787-10-5 | C14H25NO11 |
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2-乙酰氧基-3-O-(2-乙酰氧基-2-脱氧-B-D-吡喃糖苷)-2-脱氧-A-D-半乳糖苷-4-硝基苯酯 | p-nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranosyl-(1->3)-2-acetamido-2-deoxy-α-D-galactopyranoside | 125455-64-3 | C22H31N3O13 |
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2-O型(2-乙酰氨基-2-脱氧-Β-D-吡喃葡萄糖)-D-甘露糖 | N-[(2S,3R,4R,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)-2-[(2S,3S,4R,5R)-3,4,5,6-tetrahydroxy-1-oxohexan-2-yl]oxyoxan-3-yl]acetamide | 34621-73-3 | C14H25NO11 |
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2-O-alpha-D-吡喃葡萄糖基-D-半乳糖 | 2-O-(α-Glucopyranosyl)-D-galactose | 7368-73-2 | C12H22O11 |
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2-(乙酰氨基)-6-O型[2-(乙酰氨基)-2-脱氧-Β-D-吡喃葡萄糖]-2-脱氧-Α-D-半乳糖 | beta-D-GlcpNAc-(1->6)-D-GalpNAc | 452316-31-3 | C16H28N2O11 |
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1-叠氮-1-脱氧-Β-D-吡喃乳糖苷 | β-D-lactosyl azide | 69266-16-6 | C12H21N3O10 |
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—— | [(2R,5R)-4,5,6-triacetyloxy-3-[(4S,6R)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxyoxan-2-yl]methyl acetate | 3616-19-1 | C28H38O19 |
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—— | 74135-10-7 | C12H22NaO35S8 |
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—— | methyl 4,7,8,9-tetra-O-acetyl-5-(acetylamino)-2,3,5-trideoxy-2,3-didehydro-L-glycero-D-galacto-2-nonulopyranosidonate | 73960-72-2 | C20H27NO12 |
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—— | Sucrose octasulfate (potassium salt) | 73264-44-5 | C12H22KO35S8 |
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—— | 114870-03-0 | C31H53N3NaO49S8 |
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—— | 15'(=α)-Acetyldigoxin | 5511-98-8 | C43H66O15 |
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—— | α-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl-(2→1)-α-D-glucopyranoside | 470-69-9 | C18H32O16 |
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—— | D-allo-[2]heptulose | 654-29-5 | C7H14O7 |
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—— | Methyl-b-cyclodextrin | 128446-36-6 | C54H94O35 |
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—— | (2R,6R)-2-methyl-6-[[(2S)-2-(sulfanyloxymethyl)-2H-furan-5-yl]oxy]-2,6-dihydropyran | 74135-10-7 | C12H14O35S8*8Na |
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—— | cyclo<->4)-<O-α-D-mannopyranosyl-(1->4)>5-O-α-D-mannopyranosyl-(1->> | 10016-20-3 | C36H60O30 |
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—— | cyclo<->4)-<O-α-D-mannopyranosyl-(1->4)>5-O-α-D-mannopyranosyl-(1->> | 10016-20-3 | C36H60O30 |
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—— | α-cyclodextrin | 10016-20-3 | C36H60O30 |
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—— | D-Galactose, O-β-D-galactopyranosyl-(1→4)-O-β-D-galactopyranosyl-(1→4)- | 1109-28-0 | C18H32O16 |
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—— | β-ACETYLDIGOXIN | 5355-48-6 | C43H66O15 |
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