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Biochemistry-Carbohydrates

分类: 文章 • 2023-11-10 21:54:34

Carbohydrates

Monosaccharides

stereoisomers of monosaccharides

  • unbranched carbon chains
  • classification: { s t r u c t u r e : { a l d o s e k e t o s e n u m b e r : t r i o s e s , t e t r o s e s , p e n t o s e s , h e x o s e s , h e p t o s e s \begin{cases}structure:\begin{cases}aldose\\ketose\end{cases}\\ number:trioses, tetroses, pentoses, hexoses, heptoses\end{cases} ⎩⎪⎨⎪⎧​structure:{aldoseketose​number:trioses,tetroses,pentoses,hexoses,heptoses​
  • stereoisomers:n chiral carbons → 2 n \rightarrow 2^n →2n stereoisomers
  • { e n a n t i o m e r s : m i r r o r i m a g e s e p i m e r s : o n l y o n e \begin{cases}enantiomers: mirror\quad images\\epimers:only\quad one\end{cases} {enantiomers:mirrorimagesepimers:onlyone​
  • the way to represent them
    • ball-and-stick models
    • fischer projection formulas
    • perpective formulas
  • DL
    • the reference carbon: the chiral center most distant from the carbonyl carbon
    • -OH isomer
      right D
      left L
  • RS
    • 4 ⟶ \longrightarrow ⟶ 3 ⟶ \longrightarrow ⟶ 2 ⟶ \longrightarrow ⟶ 1
      − H , − D , − T , − C H 3 , − C 6 H 5 , − C H 2 O H , − C H R O H , − C H O , − C O N H 2 , − C O O H , − C O O R , − N H 2 , − N H R , − O H , − O R , − O C O R , − S H -H, -D, -T, -CH_3, -C_6H_5, -CH_2OH, -CHROH, -CHO, -CONH_2, -COOH, -COOR, -NH_2, -NHR, -OH, -OR, -OCOR, -SH −H,−D,−T,−CH3​,−C6​H5​,−CH2​OH,−CHROH,−CHO,−CONH2​,−COOH,−COOR,−NH2​,−NHR,−OH,−OR,−OCOR,−SH

cyclization of monosaccharides

  • aldehyde + alcohol ⟷ \longleftrightarrow ⟷ hemiacetal ⟷ \longleftrightarrow ⟷ acetal
    ketone + alcohol ⟷ \longleftrightarrow ⟷ hemiketal ⟷ \longleftrightarrow ⟷ ketal
  • the position of the hydroxylgroup on the anomeric carbon: { o p p o s i t e : α s a m e : β \begin{cases}opposite:\alpha \\same:\beta \end{cases} {opposite:αsame:β​
  • pyranoses and furanoses
    • n-membered oxygen-containing rings name
      six pyranoses
      five furanoses
  • how are the carbon chains shown as Haworth perspective formulas
    • left → \rightarrow → up
    • right → \rightarrow → down
    • − C H 2 O H → -CH_2OH \rightarrow −CH2​OH→ up (D)
    • − C H 2 O H → -CH_2OH \rightarrow −CH2​OH→ down (L)
  • the anomeric carbon of sugar acting as reducing agents
    • Fehling’s test(alkaline conditions)
      process
      F e 3 + → F e 2 + Fe^{3+}\rightarrow Fe^{2+} Fe3+→Fe2+
      C u 2 + → C u + Cu^{2+}\rightarrow Cu^{+} Cu2+→Cu+
      carbonyl carbon → \rightarrow → carboxyl group
  • colorimetric glucose analysis

representative monosaccharides

  • { D − G l y c e r a l d e h y d e 甘 油 醛 D − E r y t h r o s e 赤 鲜 糖 D − R i b o s e 核 糖 ， D − A r a b i n o s e 阿 拉 伯 糖 ， D − X y l o s e 木 糖 D − G l u c o s e 葡 萄 糖 ， D − M a n n o s e 甘 露 糖 ， D − G a l a c t o s e 半 乳 糖 \begin{cases}D-Glyceraldehyde甘油醛\\D-Erythrose赤鲜糖\\D-Ribose核糖，D-Arabinose阿拉伯糖，D-Xylose木糖\\ D-Glucose葡萄糖，D-Mannose甘露糖，D-Galactose半乳糖\end{cases} ⎩⎪⎪⎪⎨⎪⎪⎪⎧​D−Glyceraldehyde甘油醛D−Erythrose赤鲜糖D−Ribose核糖，D−Arabinose阿拉伯糖，D−Xylose木糖D−Glucose葡萄糖，D−Mannose甘露糖，D−Galactose半乳糖​
    Biochemistry-Carbohydrates
    Biochemistry-Carbohydrates
    Biochemistry-Carbohydrates
    Biochemistry-Carbohydrates

  • { D i h y d r o x y a c e t o n e 二 羟 基 丙 酮 D − E r y t h r u l o s e 赤 藓 酮 糖 D − R i b u l o s e 核 酮 糖 ， D − X y l u l o s e 木 酮 糖 D − F r u c t o s e 果 糖 \begin{cases}Dihydroxyacetone二羟基丙酮\\D-Erythrulose赤藓酮糖\\D-Ribulose核酮糖，D-Xylulose木酮糖\\D-Fructose果糖\end{cases} ⎩⎪⎪⎪⎨⎪⎪⎪⎧​Dihydroxyacetone二羟基丙酮D−Erythrulose赤藓酮糖D−Ribulose核酮糖，D−Xylulose木酮糖D−Fructose果糖​
    Biochemistry-Carbohydrates
    Biochemistry-Carbohydrates

Hexose Derivatives

Biochemistry-Carbohydrates

oligosaccharides

  • type feature representation
    reducing disaccharides with free anomeric carbon maltose(Glc( α 1 → 4 \alpha 1\rightarrow 4 α1→4)Glc), lactose(Gal( β 1 → 4 \beta 1\rightarrow 4 β1→4)Glc)
    nonreducing disaccharides anomeric carbon invovled in the glycosidic linkage sucrose(Fru( 2 β ↔ α 1 2\beta \leftrightarrow \alpha 1 2β↔α1)Glc), trehalose(Glc( α 1 ↔ 1 α \alpha 1\leftrightarrow 1\alpha α1↔1α)Glc)

polysaccharides

homopolysaccharides同（聚）多糖

  • srorage homopolysaccharides
    • glycogen糖原
    • starch淀粉(amylose直链淀粉、amylopectin支链淀粉)
  • structural homopolysaccharides
    • dextran葡聚糖
    • cellulose纤维素
    • chitin几丁质
  • name component chains node character
    glycogen glucose α 1 → 4 \alpha 1\rightarrow 4 α1→4, about 8-12 residues α 1 → 6 \alpha 1 \rightarrow 6 α1→6 only one reducing end
    starch(amylose) glucose α 1 → 4 \alpha 1\rightarrow 4 α1→4 / one reducing end
    starch(amylopectin) glucose α 1 → 4 \alpha 1\rightarrow 4 α1→4, about 24-30 residues α 1 → 6 \alpha 1 \rightarrow 6 α1→6 only one reducing end
    dextran glucose α 1 → 6 \alpha 1\rightarrow 6 α1→6 α 1 → 3 \alpha 1\rightarrow 3 α1→3(some have α 1 → 2 \alpha 1\rightarrow 2 α1→2 or α 1 → 4 \alpha 1\rightarrow 4 α1→4) formed by bacteria
    cellulose glucose β 1 → 4 \beta 1\rightarrow 4 β1→4 / can be broken by enzyme cellulase
    chitin N-acetylglucosamine β 1 → 4 \beta 1\rightarrow 4 β1→4 / water-insoluble

heteroploysaccharides杂多糖

  • peptidoglycan肽聚糖
  • agar琼脂
    • agarose琼脂糖
    • agaropectin琼脂胶
  • glycoasminoglycans氨基葡聚糖
  • name component chains node character
    peptidoglycan N-acetylglucosamine(GlcNAc乙酰葡萄糖胺), N-acetylmuranmic acid(Mur2Ac乙酰胞壁酸) β 1 → 4 \beta1\rightarrow 4 β1→4 cross-linked by short peptides can be hydrolyzing by the enzyme lysozyme
    agarose D-galactose, L-galactose derivative α 1 → 3 \alpha 1\rightarrow 3 α1→3(C-3 and C-6) / in some seaweeds
    agaropectin D-galactose, L-galactose derivative α 1 → 3 \alpha 1\rightarrow 3 α1→3(C-3 and C-6) branched in some seaweeds
  • glycosaminoglycans(GAGs)氨基葡聚糖
    name compoenet small chain node character
    hyaluronate透明质酸 D-glucuronic acid葡萄糖醛酸, N-acetyl-glucosamine乙酰葡萄糖胺 β 1 → 3 \beta 1\rightarrow 3 β1→3 β 1 → 4 \beta 1\rightarrow 4 β1→4 serve as lubricants
    chondroitin sulfate硫酸软骨素 β 1 → 3 \beta 1\rightarrow 3 β1→3 β 1 → 4 \beta 1\rightarrow 4 β1→4 contribute to the tensile
    dermatan sulfate α 1 → 3 \alpha 1\rightarrow 3 α1→3 β 1 → 4 \beta 1\rightarrow 4 β1→4 contribute to the pliabity
    keratan sulfate硫酸角质素 β 1 → 4 \beta 1\rightarrow 4 β1→4 β 1 → 3 \beta 1\rightarrow 3 β1→3 have no uronic acid
    heparin肝素 α 1 → 4 \alpha 1\rightarrow 4 α1→4 α 1 → 4 \alpha 1\rightarrow 4 α1→4 anticoagulant
    heparan sulfate硫酸乙酰肝素 β 1 → 4 \beta 1\rightarrow 4 β1→4 α 1 → 4 \alpha 1\rightarrow 4 α1→4 sequence heterogeneity不均一性

glycoconjugates糖复合物

glycoproteins（糖蛋白GPs）

  • a protein with small oligosaccharides attached

  • anomeric carbon attached to amino acid

  • name symbol
    O-linked oligosaccharides one yellow square
    N-linked oligosaccharides two blue square

    Biochemistry-Carbohydrates

  • lectin凝集素

glycolipid糖脂:lipopolysaccharides脂多糖

proteoglycans(PG蛋白聚糖)

  • different GAGs are covalently linked to the core protein

  • trisaccharide bridge:Gal → \rightarrow →Gal → \rightarrow →Xyl
    Biochemistry-Carbohydrates

  • aggrecan聚集蛋白聚糖

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