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GUTS session on carbohydrates and glycolipids

Dr. Arrel Toews (say Tavz, like “waves”) 420 ME Jones Building atoews@med.unc.edu 843-8727. GUTS session on carbohydrates and glycolipids. A primer on carbohydrate and glycolipid structure, nomenclature, properties, and general functions.

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GUTS session on carbohydrates and glycolipids

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  1. Dr. Arrel Toews (say Tavz, like “waves”) 420 ME Jones Building atoews@med.unc.edu 843-8727 GUTS session on carbohydrates and glycolipids A primer on carbohydrate and glycolipid structure, nomenclature, properties, and general functions See also the GUTS carbohydrate/glycolipid notes (.doc) - self-assessment exam - additional information

  2. oxidation carbohydrates reduction fats REDUCTION:(just the opposite) - gain of e- - gain of H - loss of O OXIDATION: -loss of e- -loss of H -gain of O   OXIDATION STATES OF CARBON: You better know!! O H H O O l l ll ll ll R - C - H R - C - OH R - C - H R - C - R R - C - OH O=C=O l l H H saturatedalcoholaldehydeketonecarboxyliccarbonhydrocarbonaciddioxide

  3. H O H O = aldehyde aldehyde aldehyde group group group l l C — OH C C — — OH OH C C H H H 2 2 2 l l l l l l = ketone group ketone ketone group group C O C C O O H — C — H H OH — — C C — — OH OH l l l l l l H — OH H H — — OH OH H — H H OH — — OH OH C C C C C C 2 2 2 2 2 2 Dihydroxyacetone Glyceraldehyde (a ket ose ) ) (an ald ald ose) SUGARS–CARBOHYDRATES-“hydrates of carbon” Sugars - polyalcohols (-OH) + aldehyde = aldoseor + ketone = ketose General formula: (CH2O)n Need for: - energy fuel - energy storage - cell membranes/walls - cell-cell interactions Simple sugars – monosaccharides 2 sugars – disaccharides sugar polymers - polysaccharides

  4. O H-C lH-C-OH lHO-C-H lH-C-OH l H-C-OH lCH2OH OH H-C lH-C-OH lHO-C-H lH-C-OH lC lCH2OH 1 2 3 O 1 HOCH2 6 4 O 2 H 5 H H 5 4 3 1 OH H 6 3 2 HO OH 4 Open-chainstructure H OH 5 CH OH 6 2 O O Fischer projection Shorthand method of drawing sugar structures(l=OH; C & H understood) Space-filling model Variouswaystovisualizethestructureofglucose C1 Ring structure(Haworth projection)

  5. HOCH2 C1-OH 6 O H 5 H H = 4 1 OH H O H-C lH-C-OH lHO-C-H lH-C-OH l H-C-OH lCH2OH 3 2 1 HO OH HOCH2 H OH 6 2 OH H 5 3 H 4 1 OH H HOCH2 4 3 2 6 HO O H 5 5 H OH OH H H C O 4 1 6 OH H 3 2 H HO H OH Glucose likes to form a ring in solution This is important for glycosidic links (hooking sugars together) - OH on C5 links to C1 (aldehyde C)- C1 changes from aldehyde to alcohol- 6-sided (5-C, 1-O) ring forms -glucose = Constantly opening/closing but prefers ring Glucose(open-chain form) -glucose

  6. HOCH2 CH2OH O 5 2 H HO H OH H OH C2-OH CH2OH lC HOCH2 OH 5 = 2 H HO H O H OH Fructose likes to form a ring too!! - OH on C5 links to C2 (ketone C)- C2 changes from ketone to alcohol- 5-sided (4-C, 1-O) ring forms H2-C-OH lC O lHO-C-H lH-C-OH l H-C-OH lCH2OH 1 2 3 4 = 5 -fructose(ring form) 6 fructose Constantly opening/closing but prefers ring

  7. O-l-O-POl Ol CH2lH-C-OHl C O-l-O-POlO l CH2 O-l-O-POl Ol CH2l C Ol CH2OH 6 O H H H OH H HO OH H O H OH Phosphorylated sugars are “activated intermediates” kinase sugar + ATP sugar~P+ADP • Sugar~Pare“primed for metabolism”–extra energy • -Key intermediates in: - energy production - biosynthesis dihydroxyacetone-P glyceraldehyde-P glucose-6-P

  8. HOCH2 HOCH2 HOCH2 O 5 NH2 H H 4 1 H H H C N 3 2 H H H H H H N C OH OH CH HC C H OH OH OH OH OH D-ribose(ATP, RNA) N N O HOCH2 O O H H OH H 2 OH H H HO H NH3+ 2-deoxyribose(DNA) Important pentoses D-glucosamine(an amino-sugar) N-glycosidic links (C-N bonds) are important too Adenine Ribose Adenosine(the A in ATP)

  9. Glycosidic links between sugar monomersare formed by condensation (dehydration)reactions hydrolysis condensation HOH HOH Hydrolysis (breaking a bond by addingwater across it) of glycosidic links regenerates sugar monomers HOCH HOCH HOCH HOCH 2 2 2 2 6 6 O O H H H H H H 5 H H 5 H H H H 4 4 1 1 4 1 OH OH H H OH OH H H O 3 3 2 2 3 2 Formation of a glycosidic link locks C1 intospecific configuration (either  or ).It CANNOT open or close anymore!!This matters a lot,especially for di/polysaccharides OH HO H OH H OH Maltoseglucose(-1,4)glucose Disaccharides – 2 sugars joined by glycosidic link HOCH HOCH HOCH C1 2 2 2 6 6 a O O H H H 5 5 H H H H H H 4 1 4 1 OH H OH OH H H OH OH 3 2 3 2 OH H H O O HO H OH H OH -glucose glucose

  10. HOCH2 HOCH2 O O H H OH H H 4 1 1 OH H OH H H H HO H H OH OH -glycosidic link HOCH HOCH HOCH HOCH 2 2 2 2 6 6 O O H H HO 5 H H 5 H H H H O 4 1 1 1 4 OH OH H H OH OH H H H 3 3 2 2 3 2 OH H H OH H OH Lactose (milk sugar)galactose(14)glucose Disaccharides – 2 sugars joined by glycosidic link -glycosidic link (C1-OH is ) O Cellobioseglucose(14)glucose Sucrose(fruit sugar)glucose + fructose

  11. 1 4 (14 links) 1 6 1 1 4 4 1 4 (14 links) Important glucose polymers AMYLOSE (starch in plants)long linear chains AMYLOPECTIN (starch in plants) & GLYCOGEN (animals)branched chains (14 links in chains with 16 links at branches) CELLULOSE (in plants)long linear chains

  12. Glycosaminoglycans (GAGs) aka mucopolysaccharides long chains of disaccharide-repeat units - acidic sugar (- charge) - acetylated amino sugar (no charge) Important components of: - extracellular matrix - synovial fluid of joints - mucus - vitreous humor of eye Proteoglycans – proteins with lots of GAG chains attached

  13. Repeating disaccharides in hyaluronic acid HO O Acetylation of NH2 group (otherwise present as NH3+)prevents protonation, so no (+) charge present An example of glycosaminoglycan (GAG) repeat units Don’t worry about the structures;just note the (-) charge COO- CH2OH O O OH (repeat) O (repeat) ...... ....... OH NH-C-CH3 llO GlucuronateN-acetyl-(acidic) glucosamine

  14. Other GAGs have even more (-) charges! HO O Sulfate (SO4=) groups on various –OH (and to variable degrees) in other GAGs. Sulfation makes them even more negative SO4= SO4= SO4= COO- CH2OH O O OH (repeat) O (repeat) ...... ....... OH NH-C-CH3 llO

  15. Remember Sphingolipids?? Structures and properties are generally similar to phospholipids (amphipathic) Phospholipids long hydrophobic tail polar head sugar(s) O Long-chain amino alcohol (sphingosine) (usually) F A T T Y A C I D (Glyco) Sphingolipids

  16. if X=P-choline, the molecule is sphingomyelin A primer on sphingolipid nomenclature OH X O S p h i n g o s i n e (trans) NH F A T T Y A C I D O C base molecule is sphingosine (in black above) long-chain fatty acid (several different ones) if X=H, the molecule is ceramide (base of all sphingolipids) if X=galactose, the molecule is cerebroside (galactosyl-ceramide, an important myelin lipid) if X=galactose-sulfate, the molecule is sulfatide (also a myelin component) if X=glucose, the molecule is glucosyl-ceramide (precursor to gangliosides, globosides)

  17. Vocabulary – do you know the meaning of the following terms? oxidation vs reductionsugarsmono-, di-, and polysaccharidesglucosefructoselactosesucroseglycogenstarch (amylose and amylopectin)glycosaminoglycan (mucopolysaccharide)proteoglycansphingolipidsphingosineceramidesphingomyelincerebroside (and sulfatide)

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