1 / 24

Carbohydrates: Structure and Function

Carbohydrates: Structure and Function. Sugar features 3 carbon minimum; aldehyde or ketone present; (C H 2 O) n Energy storage; lubricant; signaling. Carbohydrate Isomeric Forms. H. D- Aldose Sugar Configurations. Numbering begins at the carbonyl end of the sugar Penultimate

dmccracken
Download Presentation

Carbohydrates: Structure and Function

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Carbohydrates: Structure and Function • Sugar features • 3 carbon minimum; aldehyde or ketone present; (C H2O)n • Energy storage; lubricant; signaling

  2. Carbohydrate Isomeric Forms H

  3. D-Aldose Sugar Configurations Numbering begins at the carbonyl end of the sugar Penultimate carbon (pink) sets L- versus D-form

  4. Isomer Classification Constitutional Isomers? Enantiomers? Diastereomers? Epimers? Anomers? What is the Enantiomer of D-Erythrose?

  5. D-Ketose Sugar Configurations Carbonyl carbon (blue) is the anomeric carbon that generates two anomeric forms in the cyclic structure Anomeric carbon switches between an achiral and chiral form

  6. PyanoseFormation by Intramolecular Linkage

  7. Furanose Formation by Intramolecular Linkage Numbering via anomeric-carbon identification?

  8. Fructose Isomers Anomeric Carbon Alpha – hydroxyl down Beta – hydroxyl up Isomer Options Constitutional or Stereo-isomers? Enantiomers or diastereoisomers? Epimers or anomers?

  9. Carbohydrate Isomeric Forms H

  10. Pictorial Representations of Glucose Cyclic form – Haworth project and chair configuration Linear form – Fisher projection Most abundant natural form? √ Why is only one configuration the most abundant form?

  11. Corn Syrup and Honey Rich in Fructose Does this isomeric exactness really matter for enjoying life? • ∆ Perceived as highly sweet Perceived as mildly sweet

  12. Reducing Sugars - Reactive Aldehydes The protein modification referred to as advanced glycosylation end products (AGE) is implicated in aging, arteriosclerosis and diabetes Hemoglobin glycosylation is a high blood- sugar marker Benedict’s reagent

  13. Disaccharide Biosynthesis via Glycosyltransferase Reaction

  14. Alpha and Beta Assignments for AnomericCarbons Only Why is frucofuranosyl labeled in a beta configuration?

  15. Flipping a Box Upright On It’s Legs Legs up shift to down Leg left shifts to right Left peg up stays up Legs in front stay front

  16. Cellulose Straight Chains β-1,4 Linkage Plant fiber-forming structural polymer Most abundant organic compound in nature Dietary fiber; not digested except by bacteria

  17. Glycogen and Starch Bent Chain α-1,4-Linkage Homopolymer for glucose storage Muscle/liver glycogen rich; 1,6 branched linkage (1 in 10) Plant tissuewith amylose(unbranched) & amylopectin (1 in 30 branching)

  18. Glycoproteins – Carbohydrates Attached to Proteins More protein than carbohydrate N-linked via Asn or O-linked via Ser or Thr Chemical signature for protein or whole cell surfaces

  19. Glycosylation of Extracellular Proteins Red blood cell stimulatory hormone: erythropoietin (EPO) Glycosylation enhances stability Endurance athletes illegally use to increase oxygen- carrying capacity EPO spiking-detection based on glycosylation patterns

  20. Modified Saccharides N- O- C-glycosidic linkages Increase biochemical versatility (e.g. chemical signaling)

  21. Glycosaminoglycan Structural Units Chitin: N-acetylglucosaminehomopolymer Present in insect, crustacean, and arachnid exoskeleton Second most abundant polysaccharide in nature

  22. GlycosaminoglycanHeteropolymers Glucosamine/galactosamine amino sugar derivatives Repeating disaccharide units with negatively charged group

  23. Proteoglycans – Polysaccharides & Proteins Lubricants , structural components, and cell adhesion Cartilage – collagen (strength) and agrecans (shock absorber) More polysaccharide than protein

  24. Chapter 11 Problems: 1, 3, 5, 7, 9, 13, 15, 17, 19, 27 and 31

More Related