Lecture 40: Glycoproteins and Lysosomal Storage Diseases

Question 1

What enzymes are lysosomal storage diseases typically associated with?

Answer 1

They have a defect in HYDROLASE ENZYME which results in the accumulation of substrate in the lysosome.

Question 2

What are lysosomes?

Answer 2

Lysosomes are organelles with degradative enzymes.

Question 3

Which type of bond do lysosomal storage diseases typically have a failure to hydrolyze?

Answer 3

Glycosidic bond

Question 4

What are glycoproteins?

Answer 4

Proteins that have oligosaccharide chains covalently attached to their polypeptide chains.

Question 5

T/F Glycogen is a glycoprotein.

Answer 5

False. Glycogen is a proteoglycan because it has a polysaccharide chain attached.

Question 6

Describe a common O-glycosidic link.

Answer 6

Link between N acetyl galactosamine and either serine/ threonine.

Question 7

Which molecule has a different O-glycosidic link?

Answer 7

Collagen.

It has a link between galactose/ glucose and the hydroxyl group of hydroxylysine.

Question 8

What are the two types of N-glycosidic links?

Answer 8

1. High mannose

2. Complex (contains more than mannose)

Question 9

What is I cell disease?

Answer 9

It is a disease where lysosomal enzyme targeting signal-mannose 6 phosphate- does not get attached so fibroblasts are missing lysosomal enzymes.

Question 10

List some characteristics of a glycosaminoglycan.

Answer 10

1. Core protein of proteoglycans are linked to it.
2. Consists of a long polysaccharide chain with repeating disaccharide motif.
3. Densely negatively charged (carboxyl and/or sulfate): polyanionic
4. Amino groups

Question 11

What are hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin, and keratin sulfate?

Answer 11

They are glycosaminoglycans.

Question 12

What kind of arrangement are proteoglycan monomers + hyalyonic acid +linker proteins in?

Answer 12

Bottle Brush Arrangment

Question 13

Which molecule is the sulfate donor (usually) in vivo?

Answer 13

PAPS (phosphoadenosine phosphosulfate)

Question 14

Which Chinese molecule caused fatalities as it was sold as a cheaper alternative to the anticoagulant heparin?

Answer 14

Hypersulfonated chondroitin sulfate

Question 15

What are mucopolysaccharidoses?

Answer 15

They are a series of hereditary diseases resulting from mutations in genes coding for degradative enzymes acting on glycosaminoglycans

Question 16

T/F Most MPS are X linked.

Answer 16

False. With the exception of Hunter Syndrome, they are all AUTOSOMAL RECESSIVE.

Question 17

What is missing in Hurler Syndrome?

Answer 17

alpha- L- iduronidase deficiciency

Question 18

What is special about Hunter Syndrome and what is lacking?

Answer 18

It is X-linked and iduronate sulfatase is lacking.

Question 19

T/F: Sanfillipo Syndrome is a disease where you obtain the same symptoms for more than one mutation.

Answer 19

True.

Question 20

Which is milder: Hunter or Hurler?

Answer 20

Hunter Syndrome.

Question 21

Accumulation of _______ is particularly associated with mental retardation.

Answer 21

Dermatan sulfate