protein function 2 Flashcards
what are the glycoproteins covalenty linked to?
oligosaccharides or polysaccharide
what is the weight of the glycoproteins?
10-15
what is the function of the glycoproteins?
protects the cell awl
cell adhesion
cell specialisation
prevent aggregation-protein folding
recognises chaperone
acts as a protease resistance
where is the N-linked glycosylation glycosylated in?
ER lumen
where is the O-linked glycosylation glycosylated in?
Golgi lumen
what does dolichol phosphate enable?
flipping
what does the dolicho phosphate function and bind to?
spans the bilayer and binds the activated sugars
what does the oligosaccharyltransferase glycosylates?
protein- happens in the secretory pathway
what are the stages of glycoprotein degradation?
- endocytosis to lysosome
- protein degrades- proteases
- remove sugars- lysosome glycosides
what is lysosomal storage diseases?
undigested substrates in the lysosomes.
what is inclusion cell diseases I- cell disease caused by?
defective phosphotransferase- enzyme in Golgi apparatus
what isInclusion-cell disease (I-cell disease) mutation?
recessive mutation in GNPTAB
what does glycosaminoglycans contain?
unbranched polysaccharides with amino sugars and acidic disaccharide repeats
what is an example of glycosaminoglycans ?
hyaluronan
what are proteoglycans?
glycoproteins with GAGS
what happens in the GAG assembly on proteins?
- tetrasaccharide is added to the serine in the golgi lumen
- repeats are then added one sugar at a time
what is the function of GAGS?
lubricates in the CT
cell adhesion to extracellular matrix
binds to cell proliferation factors
what are the stages of glycosaminoglycans degradation?
- endocytosis
- removes sugars
what is the hurler disease?
deficiency of the lysosome enzyme
what is the mutation of the hurler disease?
IDUA defect
what does IDUA defect in hurler disease encode?
alpha-L- iduronidase
what happens in a hurler disease?
GAGS are not degraded
enlarged lysosomes
excessive lysosomes stored in the facial soft tissue
what are the symptoms of hurler disease?
build up of fluid in the brain
enlarged liver, spleen
decline in intellecular function
abnormalities in the heart valve
large head
what are biogenic amines?
small organic nitrogen containing molecules that are synthesised by amino acids