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Chapter 7 Carbohydrates and Glycobi ology
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Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Jan 01, 2016

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Page 1: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Chapter 7

Carbohydrates and Glycobiology

Page 2: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Carbohydrates are everywhere

http://www.homejoin.com.tw/newpic2000/HST-40.jpghttp://www.cofc.edu/~delliss/virtuallabbook/LoadingGel/Minigel2a.jpg

http://www.99main.com/~charlief/theeyebg.gif http://sportsdrz.com/images/knee.jpg

Page 3: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Sucrose

http://graphics.stanford.edu/courses/cs348b-competition/cs348b-05/donut/fifthdonut.jpg

http://www.solarnavigator.net/solar_cola/cola_images/sucrose_table_sugar_crystals.jpg

glazed donuts

Sucrose (table sugar)

Page 4: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

What are carbohydrates?

• Carbo-hydrates are a group of organic compound that can usually represented as (CH2O)n. Glucose, fructose, and galactose are all carbohydrates.

-D-Galactose

Page 5: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Classification of carbohydrate

– carbon number– L- or D- isomers– pyranose or furanose– α or β anomers– ketose or aldose

Page 6: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Carbon number

• In addition to simple hexose such as glucose, galactose, and mannose, there are a number of sugar derivatives in which a hydroxyl group in the parent compound is replaced with another substituent, or carbon atom is oxidized to a carboxyl group.

• Therefore, researchers must give each carbon of a sugar a number.

Page 7: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Carbon numberH OC

HCC

H

CH

C

H

CH2OH

HOOH

OH

OH

CH2OH

HCC

H

CH

C

HHO

O

OH

OH

CH2OHaldose ketose

1

2

3

4

5

6

1

2

3

4

5

6

Page 8: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

L- and D- isomers

CHO

H|

-C-|OH

CH2OH

CHO

H|

-C-|

HO

CH2OH

-glyceraldehydeD -glyceraldehydeL

[]25D=+8.7˚ []25

D=-8.7˚

Page 9: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

L- and D-isomers

• Although L- and D-isomers of glyceraldehydes are truly levo-rotatory (-) and dextro-rotatory (+), L- and D- sugars are NOT. For example, L-arabinose []20

D=+105.1˚ and D-fructose []20D=-92

˚

-L-arabinose (pyranose form)

Page 10: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

How to determine L- and D-

• First, find the chiral carbon

CH- =O|

H- -OHC

H- -HC|

|OH

C

Page 11: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

How to determine L- and D-

• If there is more than one chiral carbon, then…

H-C

H-C-OH|

H2-C-OH

|H-C-OH

|

=OH2-C-OH

C=O

H-C-OH

H2-C-OH

HO-

|

|

|

|-HC

D- L-

Page 12: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

C5

Formation of the cyclic form H O

HCC

H

CH

H

CH2OH

HOOH

OH

OH

C1CH

HO

OC

H

OHCHOH

C

H

OHC HOH

CH2OH

1

5

6

anomer

Page 13: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Other sugar generate 5-member ring

C5

HCC

H

CH

CH2OH

HOO

OH

OH

2

CH2OH

H

OC

OH

OHCHOH

CH

C

HOCH2

25

6

CH2OHOH

CH2OH

anomer

Page 14: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

(few)

Page 15: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 16: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 17: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 18: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 19: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 20: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

The importance of a sialic acid

a sialic acid

Normal protein Asialo-glycoprotein:Will be removed by asialoglycoprotein receptors in the liver

Sialidase(neuraminidase)

Page 21: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Monosaccharides• Colorless, crystalline solids• Water soluble but not soluble in nonpolar solvent

• Taste sweet

Page 22: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Monosaccharides have reducing powers

http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/Grafik/fehling2.gif

Page 23: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Disaccharide is made by joining two monosaccharides

Page 24: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Lactose is only present in milk

Page 25: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Sucrose is also called table sugar

Page 26: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Trehalose is a major constituent of insect hemolymph

Page 27: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

3 ≦oligosaccharide ≦20

Page 28: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Polysaccharides

Polysaccharides can serve as fuels, structural elements, and

extracellular support.

Page 29: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 30: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Polysaccharides

• Homopolysaccharides– Starch (amylose, amylopectin)– Glycogen– Chitin

• Heteropolysaccharides– Peptidoglycan– Agar (agarose, agaropectin)– Glycosaminoglycans

Page 31: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Starch and glycogen are polymers of -D-glucose

• The main chain of starch and glycogen are consisted of -D-glucose joined by (14) glycosidic bonds.

Page 32: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

The branch point of starch and glycogen : (16)

• Amylopectin and glycogen have branchs.

Page 33: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Cellulose is a polymer of -D-glucose

Page 34: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 35: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

amylose

cellulose

Page 36: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Chitin : polymer of -N-acetyl-D-glucosamine

GlcNAc

GlcNAc

GlcNAc

GlcNAc

Page 37: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Peptidoglycan contains heteropolysaccharides

Page 38: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Agarose is very important in molecular biology applications

http://www.cofc.edu/~delliss/virtuallabbook/LoadingGel/Minigel2a.jpg

Page 39: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycosaminoglycans are heteropolysaccharides

• N-acetylglucosamine or N-acetyllgalactosamine + uronic acid (D-glucuronic or L-iduronic acid)

Page 40: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Heparin is a natural anticoagulant

Page 41: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycoconjugates• Proteoglycans – glycosaminoglycan chains covalently joined to a membrane or secreted protein

• Glycoproteins – complex oligosaccharides covalently joined to a protein

• Glycolipids – membrane lipids with oligosaccharides as hydrophilic head

Page 42: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Proteoglycans

Point of attachment

Site of attachment

Trisaccharide bridge

Page 43: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Proteoglycan aggregates

Page 44: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycoproteins• Glycoproteins are carbohydrate-protein conjugates in which the carbohydrate moieties are smaller and more structurally diverse than the glycosaminoglycans of proteoglycans.

• Anomeric carbon of carbohydrate + -OH of Ser/Thr or –NH2 of Asn

Page 45: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycophorin A• Glycophorin A has 16 oligosaccharides covalently attached to it, with total 60 to 70 monosaccharide residues.

• It is the MN antigen of human erythrocytes.

Ser1, Gly5 M

Page 46: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

O- and N-linked glycosidic linkages

Page 47: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycolipid and lipopolysaccharides are membrane components

Page 48: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Glycobiology

Carbohydrates can be served as informational

molecules

Page 49: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Sugar serves as “aging” marker of proteins

a sialic acid

Normal protein Asialo-glycoprotein:Will be removed by asialoglycoprotein receptors in the liver

Sialidase(neuraminidase)

Page 50: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Lectins• Lectins are proteins that bind carbohydrates with high affinity and specificity.

Page 51: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.
Page 52: Chapter 7 Carbohydrates and Glycobiology. Carbohydrates are everywhere  delliss/virtuallabbook/LoadingGel/Minigel2a.jpg.

Membrane lectins of H. pylori binds to membrane glycoprotein of gastric epithelial cell Membrane lectins (P-, E- and

L-selectins) play important role in the movement of immune cells