Carbs

1
Carbs
2
Carbohydrates

• Greatest biomass of biopolymers
• Polyhydroxy aldehydes and ketones
• Many functions
• Structure

• Fuel
• Energy storage
• Adhesion
• Lubrication
• signalling
• tagging for siting, function

3
Degree of polymerization

• Monosaccharides
• Storage, energy modules, metabolic intermediates
• Disaccharides, trisaccharides
• Storage
• Oligosaccharides
• Molecular Recognition
• Polysaccharides
• Structure, storage

4
Fisher Projectionsof chiral monosaccharides

• Next-to-bottom carbon hydroxyl extends to the
  right --- a D sugar cf. with L amino acid

5
fig 9-3a
6
fig 9-3b
7
Hemiacetal/-ketal structures of monosaccharides

• Reaction of an aldehyde or ketone with an alcohol
• favorable intramolecular reaction

8
fig 9-5
9
Intramolecular hemiacetals/ketals of
monosaccharides are RINGS
stereo
chair
open chain
Haworth
10
Anomers

• Sugars that vary in configuration about the
  anomeric (aldehydic or ketonic) carbon
• Convention ? hydroxyl down,
• ? hydroxyl up

11
fig 9-6
12
Fig 9-7
13
Hexose derivatives

• Amino sugars
• Acetamido sugars
• Deoxy sugars
• Fucose, rhamnose, abequose
• Other glycosidic additives
• Lactic acid
• Oxidized sugars
• Sugar phosphates

14
Fig 9-9
15
Reducing sugars

• Aldehydes are oxidized by mild agents
• Cu2 aldehyde (or ?-hydroxyketone) ? Cu
  acid
• Disaccharides react more slowly

16
Fig 9-10
17
Disaccharides

• Glycosidic linkage
• Acetal (or ketal) formed. 2nd monosaccharide
  acts as an alcohol

18
Fig 9-5 (repeat)
19
Disaccharide, cont

• Reducing
• one anomeric C not glycosidically linked
• Nonreducing
• Both anomeric Cs linked (fructose, trehalose)

20
Disaccharide nomenclature

• Nonreducing end on left
• Linkage (n?m)-
• Reducing end
• Note that nonreducing end configuration is fixed
• Reducing end can mutarotate, thus 1st component
  given as ?- or ?-, 2nd ambiguous (next slide)

21
Fig 9-11
22
Table 9-1
23
Important disaccharides

• Maltose
• Lactose
• Sucrose
• Trehalose

24
Fig 9-12
25
Table 9-2
26
Storage polysaccharides

• Plants
• Starch
• Amylose llinear polyglucose, ?-1,4 linked
  (?-D-glucopyranosyl-(1?4)-), M 106
• Amylopectin polyglucose, ?-1,4 linked, ?-1,6
  branched 1 per 24-30, M 108
• Animals
• Glycogen
• polyglucose, ?-1,4 linked, ?-1,6 branched 1 per
  24-30, M 106

27
Fig 9-15 b
28
Fig 9-14
0.10 ?m
1.0 ?m
29
fig 9-15
30
Structural Polysaccharides

• Plants
• Cellulose linear polyglucose
• ? 1,4 linked
• M 106
• Certain exoskeletons
• Chitin linear poly(N-acetyl-D-glucosamine)
• ? 1,4 linked

31
Fig 9-17a and 9-18
Cellulose
Chitin
32
Structural polysaccharides, cont

• Bacterial cell walls peptidoglycans
• Extracellular matrix of multicellular animals -
  glycosaminoglycans

33
Fig 9-19
34
Fig 9-20
35
Sugar-protein and sugar-lipid conjugates

• Glycoconjugates
• Proteoglycans
• Glycosaminoglycans bound to proteins
• Glycoproteins
• Oligosaccharides bound to proteins
• Glycolipids
• Oligosaccharides bound to lipids (heads of
  membrane lipids)

36
Fig 9-29
37
Fig 9-27