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An Introduction W.T. Winter wtwinter@syr.edu 215 Jahn Lab; x6876

Sugars and Polysaccharides. An Introduction W.T. Winter wtwinter@syr.edu 215 Jahn Lab; x6876. Overview. Monosaccharides? Oligosaccharides? Polysaccharides Glycoproteins and Proteoglycans. Carbohydrates Are Chiral Molecules. Typically but not always L – amino acids D - sugars. D.

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An Introduction W.T. Winter wtwinter@syr.edu 215 Jahn Lab; x6876

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  1. Sugars and Polysaccharides An Introduction W.T. Winter wtwinter@syr.edu 215 Jahn Lab; x6876

  2. Overview • Monosaccharides? • Oligosaccharides? • Polysaccharides • Glycoproteins and Proteoglycans

  3. Carbohydrates Are Chiral Molecules • Typically but not always • L – amino acids • D - sugars D Hence, these molecules have a measurable optical rotation, which depends upon both the monomer residues and their conformation L Glyceraldehyde

  4. Fisher Formulas Next to last carbon determines D or L New carbon is added as C1

  5. A Way to Explore Monosaccharides • John Maser at Leeds has developed a “Monosaccharide Browser” the site is http://www.beechtreecommon.org/biochemistry/monosaccharide/

  6. Epimers Differ by Configuration at One Chiral Center

  7. Sugars Prefer To Be Cyclic

  8. Hemiacetals and Cyclization Group

  9. b-D-Glucose a and b are “anomers and differ in configuration at the new chiral center formed in the cycle • In nature, open chain forms are rare. • NMR has shown that all 5 coexist with the pyranose forms occurring 99% of the time, furanose about 0.5% each and a trace of open chain

  10. Pyranose Ring Shapes Pyranose rings can form chair and boat conformers 1C44C1

  11. Sucrose • 1-2 linked alpha glucose, beta fructose • Sources sugar cane sugar beet

  12. Polysaccharides • Polysaccharides consist of sugar residues linked into a polymer. • Polysaccharides, unlike proteins or nucleic acids, are not always linear in sequence • The most abundant biomolecules in nature-about 1012 tons of cellulose are synthesized each year • Functions: structural, food storage, cell surfaces, extracellular matrices.

  13. Polysaccharides May Be the Most Diverse Biomolecules From one 6 carbon hexopyranose sugar such as glucose, you can make 11 different disaccharides and 8 of those lead to infinite polymers From one amino acid or nucleotide you can make only a single dimer. -D-Glucose-D-Glucose

  14. Cellulose: Structural polysaccharide from glucose n ~ 5000-10000 Also found in some bacteria, algae, fungi, seed hairs, and animals (tunicates or sea squirts) Microfibrils of cellulose Wood cell (fiber) cell walls are made of cellulose + lignin and hemicelluloses

  15. Starch: a-D-Glucose polymer found as an energy storage material in foods Unlike cellulose, starch can be metabolized by humans. Starches provide the bulk of the energy we obtain from grains, potatoes etc. Amylose Amylopectin

  16. Extracellular Matrix: Hyaluronic acid A regular copolymer of N-acetyl glucosamine and Glucuronic Acid (as a metal salt)

  17. HA cont Found in: • synovial fluid (knee, shoulder ) • Vitreous humor (eye- used in reconstructive eye surgery) • Skin – small amounts in all connective tissues

  18. Connective Tissues- fibrous proteins, polysaccharides, and proteoglcans

  19. Other Structural Polysaccharides • Mannans – some algae • Alginic acids – many algae • Chitin- insects, crustaceans (shrimp shell), fungi.

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