Biochem 3-7 Glycoproteins

Front 1

What is a glycoprotein?

Back 1

protein w/ one or more covalently attached carbohydrate groups

Front 2

What is the process of covalently attaching carbohydrates to proteins called?

Back 2

glycosylation

Front 3

Where does glycosylation occur?

Back 3

ER and golgi

Front 4

Why are carbohydrate groups useful to glycoproteins?

Back 4

-targeting to organelles a/o membranes
-recognition & adhesion
-resistance from proteolysis

Front 5

N-glycosidic bonds

Back 5

carbohydrate sugars attached to N of arginine

Front 6

O-glycosidic bonds

Back 6

carbohydrate sugars attached to O of serine or threonine

Front 7

Sugar added to billirubin is called _____. Sugar added to lipid is called ____.

Back 7

glucuronide, glycolipid

Front 8

Disaccharides, polysaccharides and glycosaminoglycans are examples of sugars added to _____.

Back 8

other sugars

Front 9

Sugars must be _____ to add them to anything.

Back 9

Sugar Activation:
Glucose-1-phosphate + UTP → UDP Glucose

Front 10

What can you do with activated sugars?

Back 10

Front 11

What is used to conjugate billirubin?

Back 11

UDP-glucuronate

Front 12

Addition of glucuronate to bilirubin adds a _____ charge making it more _____; the rxn is catalyzed by _____.

Back 12

negative, hydrophilic (for excretion), glucuronyltransferase

Front 13

Crigler Najjar syndrome

Back 13

-severely impaired or absent glucuronyltransferase activity
-rare
- ↑ indirect BR
-Type I most severe; kernicterus and death w/o Tx
-Type II less severe than I

Front 14

Gilbert's syndrome

Back 14

-Mildly reduced expression of glucuronyltransferase
-common in U.S.
- slightly ↑ indirect BR levels, but not detrimental
-may see increased drug sensitivity to certain drugs

Front 15

Lactose synthesis

Back 15

Front 16

Beacause _____ can be converted to galactose, you do not need dietary galactose to make lactose.

Back 16

glucose; occurs only in lactating mammary gland

Front 17

What chemical properties of GAGs are responsible for the consistency of mucous secretions and synovial fluid?

Back 17

Lots of negative charge causes them to repel one another and attract water.

Front 18

What is a proteoglycan?

Back 18

-Proteoglycans are GAGs covalently attached to a core protein
-high carbohydrate content
-often sulfated

Front 19

Is hyaluronic acid a proteoglycan?

Back 19

No; it is not attached to a core protein so it is just a GAG

Front 20

Proteoglycan carbohydrate chains are composed of repeating _____ units.

Back 20

disaccharide

Front 21

Chondroiton sulfate, Dermatan sulfate and Heparan sulfate are components of _____.

Back 21

proteoglycans

Front 22

Heparan sulfate containing proteoglycans are expressed on the surface of _____ cells where they facilitate the activity of ______.

Back 22

endothelial cells, anti-thrombin

Front 23

What differentiates glycoproteins from proteoglycans?

Back 23

-GPs have more protein, less carbohydrate
-GP carb components are shorter, less charged, and branched

Front 24

How are glycoproteins targeted to lysosomes?

Back 24

-GPs get phosphorylated on mannose residues, which targets them for lysosomes

Front 25

I-cell disease

Back 25

-Deficiency in enzyme which targets lysosomal enzymes for lysosomes
-Lysosomal enzymes get secreted instead
-Proteins buildup in lysosomes because there is a shortage of lysozomal enzymes needed to degrade them- inclusions

Front 26

glycolipids

Back 26

-lipid and carb components
-derived from ceramide and are called glycosphingolipids
-important for cell surface recognition and signalling

Front 27

Cerebrosides have ___ sugar(s) while gangliosides have ___ sugar(s).

Back 27

one, two or more

Front 28

Cerebrosides and Gangliosides

Back 28

Front 29

_____ are sulfated glycosphingolipids, important in the maintenance of myelin.

Back 29

sulfatides

Front 30

_____ on RBC cell membranes are determinants of blood type.

Back 30

glycolipids

Front 31

Lysozomal storage diseases

Back 31

-Deficiency in any one of the enzymes required for lysosomal degradation of PGs, GLs & GPs
-muccopolysaccharidoses
-sphingolipidoses
-glycoproteinoses
-I-cell disease

Front 32

_____ (such as dermatan sulfate or heparan sulfate) are detected in the urine w/ mucopolysaccharidoses.

Back 32

mucopolysaccharides (GAG components)

Front 33

Hurler and Hunter syndromes belong to what class of disorders?

Back 33

mucopolysaccharidoses

Front 34

T/F: Hunter syndrome is X-linked.

Back 34

True

Front 35

What are the 4 sphingolipidosis diseases?

Back 35

-Fabry
-Gaucher
-Tay-Sachs
-Niemann-Pick
"fuck golf, try nintendo"

Front 36

What is the most common sphingolipidosis disease?

Back 36

Gaucher

Front 37

Which sphingolipidosis is X-linked?

Back 37

Fabry

Front 38

Which sphingolipidoses are much more common in peeople of Ashkenazi Jewish descent?

Back 38

Gaucher, Tay-Sachs & Niemann-Pick