Carbohydrate Conjugation- Lecture 9/10/21 Flashcards
Aldehydes
Carbohydrate with double bond O H group on the end
Ketones
Carbohydrate with a double bond O CH2OH group on the end
Ring form of carbohydrate
In equilibrium with linear form, but ring is favored
Anomeric carbon
Carbon attached to the double bond O
Alpha form
When OH is below the ring
Beta form
When OH is above the ring
Glucoside
A ring carbon with a methyl on it
Activated sugar nucleotides
In order to make a polysaccharide, the O has to be activated by a UDP nucleotide
Maltose
Glucose a(1->4)glucose
Lactose
Galactose b(1->4) glucose
Sucrose
Glucose a(1->2) fructose
Polyglucose
Example: Glycogen, can also have 1->6 bonds
Glucosaminoglycans (GAGs)
Long, linear chains of sugars that sulfates are added to
Gangliosides
Sugars attached to lipid molecules
Glycation
Proteins reacting spontaneously with carbohydrates without enzyme activity (ex: HbA1c)
Glycosylation
Sugars added to proteins enzymatically in the lumen of ER/golgi. Can be N-linked or O-linked
O-linked glycosylation
Added to threonine or serine, sugars are added one at a time
N-linked glycosylation
14 sugars are added directly to asparagine after being assembled on dolichol phosphate
Dolichol phosphate
The specialized lipid the the N linked complex is assembled on
GAG breakdown
Stepwise in lysosomes by endo or exoglycosidases, defects are LSDs
Mucins
Major macromolecular constituents of mucus which provides barrier and lubrication
Proteoglycans
Usually consist of core protein O-linked to a glycosaminoglycan
examples of proteoglycans (2)
Basement membrane supporting endothelium
Shock absorber in knee cartilage
CRD/CBD/Lectin
Carbohydrate recognition domain/carbohydrate binding domain
Role of blood type in ulcers
H. Pylori (bacterium that causes ulcers) recognize type O sugars more easily
Selection-carbohydrate interactions in leukocyte trafficking
Random contact between sugars on leukocytes leads to “rolling” along the epithelium and movement into tissues after activation
