Glycosylation Flashcards Preview

Biochemistry MBS > Glycosylation > Flashcards

Flashcards in Glycosylation Deck (32):
1

hexose example

glucose

2

pentose exmaple

ribose

3

aldehyde example

glucose

4

ketone example

ribose

5

three sugars that are stereoisomers of the same structure

glucose, galactose and mannose

6

glycosidic linkage
-formed by what carbon
-requirement for reaction to take place

-formed by the anomeric carbon
-this anomeric carbon must be activated with UDP prior to the linkage being formed

7

alpha maltose

two glucose moleculse

8

alpha lactose

galactose and glucose

9

sucrose

fructose and glucose

10

amylopectin vs amylose

amylose is a straight chain polysaccharide whereas amylopectin is a branched polysaccharide

11

glucose vs glycogen

-glucose is a single saccharide
-glycogen is a branched polysaccharide with alpha 1,4 linkages between the straight chain monomers and alpha 1,6 linkages at the branch points

12

chondroitin

-GAG
-bone, cartilage, cornea formation

13

keratin sulfate

-GAG
-cornea connective tissue

14

dermatan sulfate

-GAG
-binds LDL to plasma walls

15

heparan sulfate

-GAG
-aortic wall, basement membrane

16

heparin

-GAG
-anticoagulant

17

hyaluronic acid

-GAG
-cell migration, lubricant
-not covalently attached to a protein

18

GAG general structure

-long linear polysaccharides
-repeating disaccharide units
-considerable negative charge (including sulfate)

19

glycolipids
-example
-

-gangliosides
-come from sugar modifications of lipids

20

glycation
-HbA1c

-non-enzymatic glycosylation of proteins
-formation of HbA1c
-simple chemical reaction of sugar and protein side chains

21

enzymatic glycosylation (conjugation)
-added to
-requirement
-specificity

-occurs to add sugars to other sugars, proteins, or lipids
-requires prior activation of sugar which is accomplished by formation of sugar nucleotides
-enzymes are specific for each different sugar being added as well as the accepting sugar molecule

22

where is the sugar of glycoproteins located

-except for O-GlcNac, they are located either in the lumen of the ER, the extracellular side of the plasma membrane , or secreted

23

O-linked glycoprotein

-largely built on Ser/Thr residues
-built one sugar at a time

24

N-linked glycoprotein

-built on Asp
-initially added to the protein in a 14 sugar block
-constructed on a dilochol phosphate lipid
-initial transfer to N is usually cotranslational in the ER

25

similaritry between construction of N and O linked glycoproteins

-they are both processed as the glycoprotein traffics from the Er through the golgi

26

glycoprotein and polysaccharide breakdown

-occurs in the lysosome with the help of many different types of enzymes
-when these enzymes fail you can get lysosomal storage diseases (mucopolysaccharidoses)

27

pompe disease

single lysosomal enzyme disease defect

28

proteoglycans

-made of over 90% sugar
-important structural components
-part of the matrix that makes up tissue structure
-found in cartilage, dentin or predentin
-hydrated so they can provid cushion
-charged so they can bind substances like growth factors and chemokines.cytokines

29

biological recognition

-often involves glycosylation
-protein recognition of carbohydrate structures usually involves a lectin domain
-deficiency disease 2)

30

examples of uses of carbs in major bodily functions
-blood type
-infection
-cell contacts

carbohydrate structures underlie the differences in ABO blood type groups, contribute to the ability of viruses (flu) or bacteria (H. pylori) to infect, and mediate cell-cell contacts (leukocyte adhesion

31

chaperon mediated protein folding

-facilitated by carbohydrate binding in the ER

32

mannose-6-phosphate

-mediates tafficking of lysosomal enzymes