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59 Cards in this Set
- Front
- Back
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In an alpha-D-glycopyranose, the C1 -OH and C5 -H are __________ In a beta-D-glycopyranose, they are _________ |
alpha: same direction beta: opposite directions |
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What is the 2 step process for protein glycation? |
1. Formation of a Schiff base (aldehyde of glucose reacts with amino of protein) 2. Amadori rearrangement leads to stable ketoamine |
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HbAIC is formed by glycation of what part of the Hemoglobin molecule? |
2 N-terminal valine residues of the 2 beta-chains |
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How does mannose differ from glucose? |
C2 epimer |
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How does galactose differ from glucose? |
C4 epimer |
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How does GlcNAc differ from glucose? |
C2 -OH is replaced with NHCOCH3 |
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How does glucuronic acid differ from glucose? |
@ C6: -CH2OH is replaced by COOH |
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How does iduronic acid differ from glucose? |
C5 epimer |
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How does GalNAc differ from GlcNAc? |
C4 epimer |
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What enzyme cleaves glycosidic-linked sialic acids? |
Neuraminidase/ sialidase |
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What is the order and linkage of lactose? |
Gal-B-1 -> 4Glc (B-1,4 linkage) |
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What are the sugars usually associated with UDP donors? |
Gal, Glc, GlcA, GalNAc, GlcNAc |
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What are the sugars usually associated with GDP donors? |
Man, Fuc |
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What are the sugars usually associated with CMP donors? |
sialic acids / neuraminic acids |
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The nucleotide sugar (sugar donor) becomes what half of the 1,4 linkage? |
The 1 half |
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What is the enzyme responsible for lactose synthesis in the mammary gland? Modifying protein? |
B-galactosyltransferase a-lactalbumin |
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What is the usually acceptor & product for B-galactosyltransferase addition of UDP-gal when NOT in the mammary gland? |
Acceptor: GlcNAc (N-acetylgluosamine) Product: N-acetyllactosamine |
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What enzyme cleaves lactose? |
Lactase / B-galactosidase |
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What is the most common O-glycosidic linkage? |
alpha linkage of GalNAc to serine or threonine |
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What is the only N-linked sugar chain (1st sugar)? |
beta linkage of GlcNAc to Asn |
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High mannose type N-glycans contain only? Complex type also contain? |
High mannose: mannose and GlcNAc Complex: Gal and sialic acid |
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What is the core shared by both high mannose and complex type N-glycosylation? |
Asn-GlcNAc-GlcNAc-Man-2 branches of Man |
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High mannose vs. complex: which is neutral and which is acidic? |
Neutral: high mannose Acidic: complex |
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Congenital Disorders of Glycosylation (CDG) are associated with.... |
abnormal synthesis of N-glycans |
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What is a normal HbA1C value? Pre-diabetic? Diabetic? |
5% 5.7-6.4 > 6.5 |
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What disease is caused by protein-energy malnutrition? Symptoms? |
Kwashiorkor Failure to gain weight, edema, dry & peeling skin, changes in hair |
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What 2 viral envelope proteins are flu strains named for? |
Hemagglutinin (H) and Neuraminidase (N) |
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What type of protein is hemagglutinin? What does it do? |
A lectin (carb-binding protein) that binds sialic acid It binds & agglutinates RBCs |
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What does neuraminidase do? |
It cleaves sialic acid from the cell surface, allowing flu to spread away from the dead host cell |
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What are some flu-treatment drugs? What is their mechanism? |
Tamiflu & Relenza Inhibit neuraminidase |
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Proteoglycans are found...(2) |
On surface of cells In the ECM |
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What is the most important proteoglycan found in the ECM? It is often found in an aggregate with? |
Aggrecan aka chondroitin sulfate-proteoglycan Hyaluronic acid |
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What types of GAGs are found in Aggrecan? |
Chondroitin sulfate and keratan sulfate |
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How is each GAG covalently linked to the core protein in Aggrecan? |
Serine-Xylose-Galactose-Galactose |
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GAGS consist of what types of repeating units? |
Repeating disaccharide units: acidic sugar - amino sugar |
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Hyaluronic acid is composed of which repeating disaccharide? What linkages? |
GlcA -B1,3- GlcNAc -B1,4- |
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Hyaluronic acid is found where? (3) |
Vitreous humor of eye, synovial fluid, loose connective tissue |
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Chondroitin sulfate is composed of which repeating disaccharide? What linkages? |
GlcA -B1,3- GalNAc -B1,4- |
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What is the difference between Chondroitin-6-sulfate and Chondroitin-4-sulfate? |
4 has a sulfated C on C4 of GalNAc 6 has a sulfated C on C6 of GalNAc |
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Where are Chondroitin-4 and -6 sulfate found? |
Cartilage, tendons, ligaments |
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Dermatan sulfate is composed of which repeating disaccharide? What linkages? |
L-IdoA-2-sulfate -a1,3- GalNAc-4-sulfate -B1,4- |
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Where is dermatan sulfate found? |
Skin, blood vessels, heart valves |
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Keratan sulfate is composed of which repeating disaccharide? What linkages? |
Gal -B1,4- GlcNAc -B1,3- *C6s on both often sulfated |
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Where is keratan sulfate found? |
Cartilage and cornea |
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Where is heparin found? Where is heparin sulfate found? |
Heparin: in mast cells in liver, lung, and vessel wall HS: extracellular component |
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Heparin / heparin sulfate is composed of which repeating disaccharide? What linkages? |
L-IdoA OR D-GlcA -a1,4 or B1,4- GlcN -a1,4- |
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What is unique about the linkages in heparin/heparin sulfate? |
All a1,4 |
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How does heparin work as an anticoagulant? |
Binds and activates Antithrombin III |
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Polysaccharide chain of a peptidoglycan contains... |
GlcNAc -B1,4- MurNAc |
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What is the tetrapeptide chain attached to lactic acid in a peptidoglycan? |
L alanine- D glutamate- L lysine- D alanine + 5 glycines |
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Where does the cross-linking occur in the peptidoglycan network? What enzyme catalyzes it? |
Between pentaglycine and D-alanine Catalyzed by transpeptidase |
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What type of antibiotics inhibit the cross-linking of peptidoglycan? |
B-lactam antibiotics (penicillin) |
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What ate the hallmarks of patients with mucopolysaccharidoses (MPS)? |
Coarse facial features, hepatosplenomegaly, bone deformity, and intellectual disability |
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Hurler/Scheie syndrome is caused by a deficiency in what enzyme? What builds up? |
a-L-Iduronidase Buildup of DS and HS |
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Hunter syndrome is caused by a deficiency in what enzyme? What builds up? |
Iduronate sulfatase Buildup of DS and HS |
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What therapy is used to treat Hunter syndrome? |
Elaprase |
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What therapy is used to treat Hurler syndrome? |
Aldurazyme/Laronidase |
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Sanfillppo syndrome is caused by a deficiency in what enzyme? (all types) What builds up? |
TA: Heparin N-sufatase TC: Acetyl-CoA acetyl transferase TB: a-N-acetylglucosaminidase HS with modifications to the exposed GlcN sugar |
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Morquio syndrome is caused by a deficiency in what enzyme? What builds up? |
A: Galactose 6-sulfatase B: B-galactosidase KS and modified KS |
