Flashcards in Lecture 40: Glycoproteins and Lysosomal Storage Diseases Deck (21):
What enzymes are lysosomal storage diseases typically associated with?
They have a defect in HYDROLASE ENZYME which results in the accumulation of substrate in the lysosome.
What are lysosomes?
Lysosomes are organelles with degradative enzymes.
Which type of bond do lysosomal storage diseases typically have a failure to hydrolyze?
What are glycoproteins?
Proteins that have oligosaccharide chains covalently attached to their polypeptide chains.
T/F Glycogen is a glycoprotein.
False. Glycogen is a proteoglycan because it has a polysaccharide chain attached.
Describe a common O-glycosidic link.
Link between N acetyl galactosamine and either serine/ threonine.
Which molecule has a different O-glycosidic link?
It has a link between galactose/ glucose and the hydroxyl group of hydroxylysine.
What are the two types of N-glycosidic links?
1. High mannose
2. Complex (contains more than mannose)
What is I cell disease?
It is a disease where lysosomal enzyme targeting signal-mannose 6 phosphate- does not get attached so fibroblasts are missing lysosomal enzymes.
List some characteristics of a glycosaminoglycan.
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
What are hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin, and keratin sulfate?
They are glycosaminoglycans.
What kind of arrangement are proteoglycan monomers + hyalyonic acid +linker proteins in?
Bottle Brush Arrangment
Which molecule is the sulfate donor (usually) in vivo?
PAPS (phosphoadenosine phosphosulfate)
Which Chinese molecule caused fatalities as it was sold as a cheaper alternative to the anticoagulant heparin?
Hypersulfonated chondroitin sulfate
What are mucopolysaccharidoses?
They are a series of hereditary diseases resulting from mutations in genes coding for degradative enzymes acting on glycosaminoglycans
T/F Most MPS are X linked.
False. With the exception of Hunter Syndrome, they are all AUTOSOMAL RECESSIVE.
What is missing in Hurler Syndrome?
alpha- L- iduronidase deficiciency
What is special about Hunter Syndrome and what is lacking?
It is X-linked and iduronate sulfatase is lacking.
T/F: Sanfillipo Syndrome is a disease where you obtain the same symptoms for more than one mutation.
Which is milder: Hunter or Hurler?