单糖是由3~7个碳原子与氢及氧原子结合形成的多羟基醛或酮,其中最简单的单糖为含3个碳原子的丙糖。随着碳原子数目的增加,依次有丁糖、戊糖和己糖等。在人体内,重要的戊糖包括核糖和脱氧核糖,它们分别组成核糖核酸与脱氧核糖核酸。生物学上最重要的三种单糖是葡萄糖、果糖和半乳糖,其共同化学式为C6H12O6。
这些单糖具有特定的结构特征:含有醛基或酮基,其中葡萄糖和半乳糖含有醛基,而果糖则含酮基。由于它们具有还原性,可用于检查尿液或血液中的糖分含量。此外,单糖还具备多个羟基,能够参与典型的酯化、成苷、脱氧、脱水及氨基化的反应。
作为许多糖类的基本单位,食物中的复杂糖类在消化后会被分解为单糖,并主要在小肠上部被吸收。不同类型的单糖吸收速度各异:葡萄糖的吸收率为100%,半乳糖为110%,果糖为43%,甘露糖为19%,木酮糖为15%,而阿拉伯糖仅为9%。
单糖不仅是构成海洋生物、海水和海洋沉积物中糖类物质的基本组分,还广泛存在于其中。在海洋浮游生物中,常见的单糖按丰度顺序包括半乳糖、葡萄糖、甘露糖、核糖、木糖、岩藻糖、鼠李糖和阿拉伯糖。多数情况下,这些单糖以多聚糖或结合形式存在于生物体内,并且也普遍存在于海水中。
在海洋环境中,果糖的来源有限,但在海水中能够通过差向异构化从葡萄糖转化而来。海水中的单糖浓度一般为0—20微克/升,通常以10微克碳/升代表总游离单糖的浓度。海水中单糖含量可通过METH法测定;对于葡萄糖,则常用酶促或生物鉴定法直接测量。在进行所有个别单糖的测定时,通常采用色谱分离方法。
由于单糖是非挥发性化合物,在使用气相色谱法检测时需要经衍生化处理。常用的液相色谱技术包括乙醇/水分配色谱和硼酸络合物离子交换色谱等。
中文名称 | 英文名称 | CAS号 | 化学式 | 结构式图片 |
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4-甲氧苯基-2,3,4,6-四-O-乙酰基-Alpha-D-吡喃甘露糖苷 | p-methoxyphenyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside | 17042-40-9 | C21H26O11 |
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4-甲氧基苯基Β-D-吡喃葡萄糖苷 | 4-methoxyphenyl β-D-glucopyranoside | 6032-32-2 | C13H18O7 |
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4-甲氧基苯基-Β-D-半乳糖苷 | 4-methoxyphenyl β-D-galactopyranoside | 3150-20-7 | C13H18O7 |
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4-甲基香豆素基-Β-L-吡喃岩藻糖苷 | 4-methylumbelliferyl-β-L-fucopyranoside | 72601-82-2 | C16H18O7 |
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4-甲基香豆素基-Β-D-吡喃岩藻糖苷 | 7-((6-Deoxy-beta-D-galactopyranosyl)oxy)-4-methyl-2H-1-benzopyran-2-one | 55487-93-9 | C16H18O7 |
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4-甲基香豆素基-Α-L-吡喃阿拉伯糖苷 | 4-methylumbelliferyl α-L-arabinopyranoside | 69414-26-2 | C15H16O7 |
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4-甲基香豆素-2-乙酰氨基-2-脱氧-β-D-吡喃葡萄糖苷 | N-[(2S,3R,4R,5S,6R)-4,5-Dihydroxy-6-hydroxymethyl-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)-tetrahydro-pyran-3-yl]-acetamide | 37067-30-4 | C18H21NO8 |
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4-甲基伞形酯-N-乙酰-Β-D-氨基半乳糖苷 | 4-methylumbelliferyl-2-acetamide-2-deoxy-β-D-galactosamide | 36476-29-6 | C18H21NO8 |
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4-甲基伞形酮酰-Β-D-吡喃葡糖酸苷 | 4-methylumbelliferyl β-D-glucopyranoside | 18997-57-4 | C16H18O8 |
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4-甲基伞形酮酰-Β-D-吡喃木糖苷 | 4-methylumbelliferyl β-D-xyloside | 6734-33-4 | C15H16O7 |
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4-甲基伞形酮基-Alpha-D-吡喃甘露糖苷 | 4-methylumbellifer-7-yl α-D-mannopyranoside | 28541-83-5 | C16H18O8 |
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4-甲基伞形酮-alpha-l-岩藻吡喃糖苷 | 4-methylumbelliferyl α-L-fucopyranoside | 54322-38-2 | C16H18O7 |
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4-甲基伞形酮-a-L-呋喃阿拉伯糖苷 | 7-hydroxy-4-methylcoumarin-7-yl α-L-arabinofuranoside | 77471-44-4 | C15H16O7 |
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4-甲基伞形酮-Alpha-D-吡喃半乳糖苷 | 4-methylumbelliferyl α-D-galactopyranoside | 38597-12-5 | C16H18O8 |
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4-甲基伞形酮-2-乙酸胺基-2-脱氧-Α-D-吡喃葡糖苷 | 4-methylumbelliferyl 2-acetamido-2-deoxy-α-D-glucopyranoside | 80265-04-9 | C18H21NO8 |
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4-甲基伞形酮 beta-D-甘露糖苷 | 4-methylumbelliferyl-β-D-mannopyranoside | 67909-30-2 | C16H18O8 |
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4-甲基-7-乙酰氧基香豆素-β-D-吡喃半乳糖苷 | 4-methylumbelliferyl-β-D-galactopyranoside | 6160-78-7 | C16H18O8 |
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4-氯苯基-Β-D-葡萄糖苷 | 2-(4-Chlorophenoxy)-6-(hydroxymethyl)oxane-3,4,5-triol | 4756-30-3 | C12H15ClO6 |
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4-氯苯基-2-乙酰氨基-3,4,6-三-氧-乙酰基-2-脱氧-Β-D-葡萄糖苷 | p-chlorophenyl 3,4,6-tri-O-acetyl-2-acetamido-2-deoxy-β-D-glucopyranoside | 50729-97-0 | C20H24ClNO9 |
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4-氯苯基-2-乙酰氨基-2-脱氧-Β-D-葡萄糖苷 | 4-chlorophenyl 2-acetamido-2-deoxy-β-D-glucopyarnoside | 50730-05-7 | C14H18ClNO6 |
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4-氯-3-吲哚基beta-D-吡喃半乳糖苷 | 4-Chloro-3-indolyl beta-D-galactopyranoside | 135313-63-2 | C14H16ClNO6 |
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4-氨基苯基-beta-l-岩藻吡喃糖苷 | 4-aminophenyl β-L-fucopyranoside | 69936-58-9 | C12H17NO5 |
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4-氨基苯基-alpha-D-吡喃甘露糖苷 | p-aminophenyl-α-D-mannopyranoside | 34213-86-0 | C12H17NO6 |
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4-氨基苯基-1-硫代-β-D-葡萄糖苷 | (2S,3R,4S,5S,6R)-2-((4-aminophenyl)thio)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol | 58737-22-7 | C12H17NO5S |
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4-异硫氰基苯基-β-D-吡喃葡萄糖苷 | 4-Isothiocyanatophenyl beta-D-glucopyranoside | 20581-41-3 | C13H15NO6S |
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4-异硫氢酸苯基-Α-D-甘露糖苷 | [p-isothiocyanato]-phenyl α-D-mannopyranoside | 96345-79-8 | C13H15NO6S |
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4,7,8,9-四-O-乙酰基-N-乙酰神经氨酸甲酯 | 4,7,8,9-tetra-O-acetyl-N-acetylneuraminic acid methyl ester | 84380-10-9 | C20H29NO13 |
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4,6-亚乙基-alpha-D-葡萄糖 | 4,6-o-ethylidene-α-D-glucose | 13224-99-2 | C8H14O6 |
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4,6-o-亚苄基-a-d-甘露糖苷甲酯 | 6-Methoxy-2-phenyl-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxine-7,8-diol | 4148-58-7 | C14H18O6 |
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4,6-O-亚苄基-D-吡喃葡萄糖 | 4,6-O-benzylidene-D-glucose | 30688-66-5 | C13H16O6 |
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3-脱氧-d-葡萄糖 | 3-deoxy-D-glucose | 2490-91-7 | C6H12O5 |
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3-羧基香豆素-Β-D-吡喃葡萄糖醛酸 | 3-Carboxyumbelliferyl-b-D-glucuronide | 216672-17-2 | C16H14O11 |
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3-羧基香豆素-Β-D-吡喃半乳糖苷 | 3-Carboxyumbelliferyl beta-D-galactopyranoside | 64664-99-9 | C16H16O10 |
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3-硝基苯-Alpha-D-吡喃半乳糖苷 | meta-nitrophenyl-α-D-galactopyranoside | 3150-25-2 | C12H15NO8 |
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3-硝基苯 β-D-吡喃半乳糖苷 | 3-nitrophenyl β-D-galactopyranoside | 3150-25-2 | C12H15NO8 |
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3-氟-3-脱氧-D-吡喃糖 | 3-deoxy-3-fluoro-D-glucose | 14049-03-7 | C6H11FO5 |
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3-吲哚基-beta-D-葡糖苷酸环己胺盐 | Indoxyl glucuronide | 35804-66-1 | C14H15NO7 |
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3-吲哚基-beta-D-吡喃葡萄糖苷 | 3-indoxyl-β-D-glucopyranoside | 487-60-5 | C14H17NO6 |
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3-吲哚基-beta-D-吡喃半乳糖苷 | (2S,3R,4S,5R,6R)-2-((1H-indol-3-yl)oxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol | 126787-65-3 | C14H17NO6 |
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3-叠氮-2,3-二脱氧基-1-O-(叔丁基二甲基甲硅烷基)-β-D-阿拉伯-六吡喃糖 | 3-azido-1-O-tert-butyldimethylsilyl-2,3-dideoxy-β-D-arabinohexopyranoside | 189454-43-1 | C12H25N3O4Si |
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3-乙酰氨基-3-脱氧-D-葡萄糖 | N-Acetyl-kanosamin | 14086-88-5 | C8H15NO6 |
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3-乙酰基伞形酮基beta-D-吡喃葡萄糖苷 | 3-acetyl-7β-D-glucopyranosyloxy | 20943-16-2 | C17H18O9 |
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3-O-苄基-4-C-羟甲基-1,2-O-异亚丙基-ALPHA-D-呋喃核糖 | 1,2-O-isopropylidene-3-O-benzyl-4-hydroxymethyl-α-D-ribofuranose | 63593-03-3 | C16H22O6 |
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3-O-苄基-1,2:5,6-双-O-异丙亚基-alpha-D-呋喃半乳糖 | 1,2:5,6-di-O-isopropylidene-3-O-benzyl-α-D-allofuranose | 22331-21-1 | C19H26O6 |
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3-O-苄基-1,2:5,6-O-双异丙叉-α-D-呋喃葡萄糖 | 3-O-benzyl-1,2-5,6-O-diisopropylidene-α-D-glucofuranose | 18685-18-2 | C19H26O6 |
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3-O-乙酰基-1,2:5,6-二-O-异丙基-Alpha-D-呋喃(型)葡萄糖 | 3-O-acetyl-1,2:5,6-Di-O-isopropylidene-α-D-glucofuranose | 16713-80-7 | C14H22O7 |
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3,5-二-O-(叔丁基二甲基硅烷)-2-脱氧-D-核糖酸-1,4-内酯 | 3,5-di-O-(tert-butyldimethylsilyl)-2-deoxy-D-ribono-1,4-lactone | 83159-91-5 | C17H36O4Si2 |
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3,4-二乙酰-L-阿醛 | 3,4-di-O-acetyl-L-arabinal | 3945-18-4 | C9H12O5 |
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3,4-二-O-乙酰-1,5-酐-2,6-双脱氧-L-阿拉伯-己-1-糖醇 | 3,4-di-O-acetyl-6-deoxy-L-glucal | 34819-86-8 | C10H14O5 |
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3,4,6-三邻苄基半乳醛 | 3,4,6-tri-O-benzyl-D-galactal | 80040-79-5 | C27H28O4 |
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