BiochemFall2017_Lecture17.pdf - Lecture 17 Chapter 9...

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Lecture 17: Chapter 9Glycoconjugates and Polysaccharides
Lecture17 Outline:Text Book: Chapter 9(Pages 332-350 )• Glycoproteins• Oligosaccharides as Cell Markers• Glycoconjugates of Interest• Structural Polysaccharides
Common five-carbon sugarsGlucose: standard six-carbon sugarGalactose and Mannose are: epimersof glucoseFructoseis the ketoseform of glucoseA quick recap of last week’s episode: Part 1Common three-carbon sugars
A quick recap of last week’s episode: Part 2Monosaccharides Cyclize to form Ring StructuresRings can be Furanose or PyranoseRings can exist in Boat or Chair Conformations: Chair more stable
Maltose: Reducing DisaccharideCondensation of two glucose molecules via 1 4 bond forms MaltoseA quick recap of last week’s episode: Part 3Test for reducing sugarsCuSO4: Bright BlueBrick Red PrecipitateNon-reducing sugarsα-D-Glc(12)-β-D-Fru
Enzymes that generate complex glycans• Monosaccharide donor is an activated nucleotide sugar; for example, UDP-GalNAc and UDP-Gal • Sequential glycosyltransferase reactions generates the initial core glycan on the O-linked glycoprotein Gal β-1,3 GalNAc α-1-SerGlycosyltransferasesGenetic differences in expression and activity of these enzymes: immunological incompatibility between individuals
GlycoconjugatesGlycoconjugates contain combinations of modified and unmodified monosaccharides, covalently attached to proteins and lipids as branched and/or unbranched structures
Glycobiology: Study of Glycan Structure & Function
Important Aspects of GlycobiologyGlycan Biochemistry, Glycan Biosynthesis, Glycan Diversity and Glycan RecognitionEntryActivationAttachmentChain ElongationDisplay on Cell Surface
Important Biological Functions of Glycoconjugates: Glycoproteins & ProteoglycansGlycoproteins:Bulk of macromolecules consists of protein.

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