Biochemistry Flashcards
Another name for a proteoglycan
Sugar backbone + protein
Mucopolysaccharide
A GAG consists of
Repeating disaccharide units of: acid sugar (glucuronic acid, iduronic acid) & amino sugar (glucosamine, galactosamine)
6 major groups of GAG include:
- CS #1 (cartilage, bone, heart valves)
- Hyaluronic acid (no sulfate, not covalently attached to proteins)
- KS
- DS
- Heparan Sulfate (negatively charged, acetylated glucosamine)
- Heparin (more sulfated than HS)
Cartilage consists of these GAGs (3)
CS, KS, hyaluronic acid
How is a GAG linked to a protein to form a proteoglycan?
Trihexoside linkage (gal-gal-xy) + serine
GAG’s are synthesized using what enzymes
Glycosyl transferases
Who is the sulfate donor when it comes to proteoglycan synthesis?
PAPS (with sulfrotransferase)
What is I cell disease?
Inability to transport hydrolytic enzymes to lysosomes 2/2 to inability to phosphorylate mannose
- Skeletal abnormalities, psychomotor, no joint movement
- Substances accumulate in lysosome; enzymes accumulate in plasma
O-glycosidic links in glycoproteins are made by…
OH- of serine/threonine
What are several examples of glycoproteins?
Cell surface receptors, blood group Ag, collagen, fibronectin
The pathogenesis of E. coli & H. pylori as it relates to glycoproteins
E. coli: mannose in plasma membrane
H. pylori: gastric epithelium
COPI vs COP2 cellular trafficking
What about clathrin?
COP1: retrograde: Golgi –> ER
COP2: anterograde: ER –> Golgi
Clathrin: Golgi –> Lysosomes; Plasma membrane –> Endosomes
What GAG can be injected into the joints of patients with osteoarthritis?
Hyaluronic acid
Fabry’s disease: deficient enzyme
Alpha-galactosidase
Gaucher’s disease: deficient enzyme
Glucocerebrosidase
Niemann-Pick disease: deficient enzyme
Sphingomyelinase
Tay-Sachs disease: deficient enzyme
Hexosaminidase A
Krabbe’s disease: deficient enzyme
Galactocerebrosidase
Metachromatic leukodystrophy: deficient enzyme
Aryl sulfatase
Hurler’s syndrome: deficient enzyme
Alpha-L-iduronidase
Hunter’s syndrome: deficient enzyme
Iduronate sulfatase
X-linked lysosomal storage disorders
Hunter’s, Fabry’s
Cherry-red spot macula lysosomal storage disorders
Tay-Sachs, Niemann-Pick (+HSM)
Corneal clouding lysosomal storage disorders
Hurler’s disease