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Sugar Chemistry

    Why study sugars? Most cells are sheathed in coatings made up of hetero-polymers of a wide variety of sugars and their derivatives. Thus this is of very significant immunological consequence: self/nonself recognition; tissue compatability; pathogen recognition; pathogen evasion of recognition, etc., etc, etc.

1. Reducing Sugars (Haworth and Fisher structures with mnemonics)
   1. Mutarotation

   2. Composition at equilibrium
      
      
      
      

2. Types of Isomerism in Sugars
   1. Enantiomorph (see Recognizing D,L-Haworth Structures mnemonic)

   2. Diastereoisomer

   3. Epimer
      
      

3. Sugars and their Derivatives
   1. Redoxed forms (previous lecture)

   2. Methyl Glycosides, as in spices
      
      
      
      

   3. Amines, as in N-Ac-glucosamine, a major membrane component.
      
      
      
      

4. in vitro Chemical Reactions
   1. Dehydration (caramels, etc.) furfurals
      
      
      
      

   2. Periodate Oxidation (HIO₄) - See lab notes.
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      

5. Polymerized sugars
   1. Disaccharides

      
      α-D-glucopyranosyl-(1,2)-β-D-fructofuranoside
      catabolic enzyme = invertase

      
      β-D-galactopyranosyl-(1,4)-β-D-glucopyranoside
      catabolic enzyme = maltase

      
      α-D-glucopyranosyl-(1,4)-β-D-glucopyranoside
      catabolic enzyme = lactase (eukaryotes) or β-galactopyranosidase (prokaryotes)
      

   2. Trisaccharides

   3. Higher polymers
      1. 

      2. glycogen and amylopectin

      3. cellulose
         

      4. Lipopolysaccharide (LPS)

      5. Blood groups:

         Type	X
         A	N-acetyl-gal
         B	gal
         O	---

         (fucose = 6-deoxy-α-L-mannose)

      6. Agar

      7. Pectin