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Biochemistry- Ch 11. Carbohydrates. 阮雪芬 NTUT Nov 4, 2002. Monosaccharides. The simplest carbohydrates (C-H 2 O) n Carbon hydrate. Trioses. enantiomers. D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms. D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms.
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Biochemistry-Ch 11. Carbohydrates 阮雪芬 NTUT Nov 4, 2002
Monosaccharides • The simplest carbohydrates • (C-H2O)n • Carbon hydrate
Trioses enantiomers
D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms
D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms
D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms
D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms
D-Aldoses Containing Three, Four, Five, and Six Carbon Atoms
D-Ketoses Containing Three, Four, Five, and Six Carbon Atoms
D-Ketoses Containing Three, Four, Five, and Six Carbon Atoms
D-Ketoses Containing Three, Four, Five, and Six Carbon Atoms
Ring Structures of Fructose • a: hydroxyl group attached to C-1 is below the plane of the ring. • b: hydroxyl group attached to C-1 is above the plane of the ring.
Conformation of Pyranose and Furanose Rings • Pyranose and Furanose Rings are not planar.
Chair and Boat Forms of b-D-glucopyranose • The chair form is more stable.
Envelop Conformations of b-D-ribose • Four atoms are nearly coplanar and the fifth is about 0.5Å away from this plane. 5 5 3 4 4 2 3 1 1 2
O-glycosidic bond and N-glycosidic bond NR2: N-glycosidic bond
Common Disaccharides (1) Sucrase fructose glucose
Common Disaccharides (2) Lactase: in human beings b-galactosidase: in bacteria glucose galactose
Common Disaccharides (3) Maltase glucose glucose
Polysaccharides • Large polymeric oligosaccharides • Play vital roles in energy storage and in maintaining the structural integrity of an organism. • If allof the monosaccharides are the same,these polymers are called homopolymers. • In animal cells: Glycogen • In plants: Starch • Amylose: the unbranched type • Amylopectin: the branched type
Branch Point in Glycogen Once in 10 units (glycogen) Once in 30 units (starch)
Starch and Glycogen • Starch:
Cellulose • One of the most abundant organic compounds in the biosphere. • The major structural polymer of plants • Consists of linear chains of glucose units
Glycosaminoglycans • A different kind of repeating polysaccharide is present on the animal cell surface and in the extracellular matrix. • Many glycosaminoglycans are made of disaccharides repeating units containing a derivative of an amino sugar, either glucosamine or galactosamine