Carbohydrate conjugation Flashcards
exam 2
1
Q
hexose
A
glucose
2
Q
pentose
A
ribose
3
Q
carbohydrates as aldehydes
A
glucose
4
Q
ketones
A
fructose
5
Q
what do glucose, galactose and mannose have in common?
A
they are steroisomers
6
Q
anomeric carbon
A
carbon where you could connect other molecules together
7
Q
alpha-glycosidic bond
A
pointed down or below the plane
8
Q
beta- glycosidic bond
A
pointed up or above the plane
9
Q
linkages that our enzymes cannot cleave… found in dental plaque or cellulose
A
Dextrans
10
Q
Beta-Glactose + Beta-Glucose
A
lactose
11
Q
Glucose + Glucose
A
maltose
12
Q
Glucose + Fructose
A
Sucrose
13
Q
amylose
A
plant starch
14
Q
Amylopectin
A
plant starch
15
Q
glycogen
A
human polyglucose
16
Q
anti coagulant
A
Heparin
17
Q
General GAG structure
A
long, linear polysaccharides, with repeating disaccharide units, with considerable negative charge (including sulfate)
18
Q
1-4 alpha linkages leading to a linear shape
A
amylose
19
Q
1-4 alpha linkages and 1-6 alpha branch linkages
A
glycogen and amylopectin
20
Q
1-4 beta linkages
A
cellulose
21
Q
humans lack the enzymes needed to digest 1-4 beta linkages
A
cellulose
22
Q
for plant rigidity
A
cellulose
23
Q
what is very important for connective tissues and allows for hydration?
A
GAGs
24
Q
found in bone cartilage, cornea formation
A
chondrotin sulfate
25
found in intracellular fluid in synovial joints and in vitreous fluid of eye
hyaluronic acid
26
cornea connective tissue
keratan sulfate
27
binds to LDL to plasma walls
dermatan sulfate
28
aortic wall, basement membrane
heparan sulfate
29
what are rich in the nervous system?
gangliosides
30
example of a sugar that can be conjugated to lipids
gangliosides
31
galngliosides are used
in glycoprotein hormone receptors
32
Glucuronic conjugation to small molecules enhances
their solubility
33
non-enzymatic glycosilation of proteins
glycation
34
formation of hemoglobin A1c occurs by
glycation: simple rxn. of protein side chains and carbohydrate
- no cofactor needed
35
occurs to add carbohydrate to other carbohydrates, to proteins or to lipids
Enzymatic glycosylation
36
enzymatic conjugation requires _____ ______ of sugar that is accomplished by formation of _____ _____
enzymatic conjugation requires prior activation of sugar that is accomplished by formation of sugar nucleotides
37
enzymatic formation of polysaccharides occurs
one sugar at a time using an enzyme of the correct specificity and the appropriate substrate
38
Glucuronic Acid is activates w/UDP and is added to
non-soluble molecules like lipids and drugs to make them more soluble
39
Glucuronic acid is added to bilirubin to make bilirubin
soluble
40
Glucuronic Acid conjugation needs
UDP-Glucuronysltransferase (UGT)
41
occurs when low UGT activity leads to high bilirubin levels
Gilbert's syndrome
42
what causes Gilbert's syndrome?
UGT activity is low or it is inherited with a heterozygous condition
43
associated with aging
ketoamines
44
provides a history of glucose levels
HbA1C
45
rxn initially forms schiff base then rearranges to ketoamine
glycation
46
Perlecan is an example of a proteoglycan. Which of the following statements about the glycosaminoglycans that are found in proteoglycans is true:
A. They are positively charged.
B. They contain repeating disaccharides.
C. They have branched high mannose structures.
D. They have short oligosaccharide chains.
E. They rarely contain sulfate.
B. They contain repeating disaccharides.
47
Glycosylation is for
secreted proteins or extracellular domains
48
What is so special of O-linked N-Acetylglusocamine?
can be added to proteins not being secreted or extracellular
49
Can be O-linked or N-linked
Glycosylation
50
O-linked anomeric carbon
serine and threonin
51
N-linked anomeric carbon
Asparagine
52
Glycosylation that is done sequentially (one-step at a time) in the GOLGI, along with trimming and modification
O-linked
53
O- linked Glycosylation is done
post-translationally
54
the precise sequence of the carbohydrate chain depends on enzyme specificity for (2)
(1) a given sugar nucleotide
| (2) a given acceptor of the sugar
55
glycosylation that can add sugar residues of around 14 at once
N-linked glycosylation
56
N-linked Glycosylation occurs in the
membrane of the ER, on Dolichol Phosphate (lipid molecule0
57
N-linked Glycosylation occurs
co-translationally or shortly after
58
sugar block used in N-linked glycosylation is first made on the _______ then transferred to protein in _____
first made on Dolichol phosphate and then transferred to the ER
59
Congenital disease of Glycosylation
can be both O/N- linked
| - presents with varied symptoms
60
contains many enzymes that degrade glycoprotein/polysaccharide sugars
lysosome
61
lysosomal storage diseases
mucopolysaccharidoses
62
serious diseases that are generally characterized by cellular inclusions
lysosomal storage diseases
63
lysosomal storage diseases are caused b
enzyme defects
64
lysosomal storage diseases of a single enzyme
Pompe
65
lysosomal storage diseases of multienzyme
I-cell disease
66
When carbohydrates covalently attach to proteins without the intervention of enzymes or any need for cofactor, the process is called ??
glycation
67
A three month old child has muscle hypotonia and feeding problems. There is also hepatomegaly and cardiomegaly. Muscle biopsy shows accumulation of polysaccharride in the lysosomes. Which enzyme is deficient?
A. Glucose 6-phosphatase
B. Glycogen phosphorylase
C. Acidic alpha-glucosidase
D. Galactokinase
E. Branching enzyme
C. Acidic alpha-glucosidase
68
in molecular recognition
glycosylation
69
iduronate sulfatase
hunter
70
alpha-L-Iduronidase
Hurler + Sheie A
71
Acid alpha glucosidase
Pompe
72
Beta-Glucuronidase
Mucolipidosis VII
73
lysosomes have _______ (cleave in middle) and ________ (cleave from end)
endoglycosidases and exoglycosidases
74
polysaccharide breakdown is a
stepwise process
75
principle component of mucus that line and protect epithelial surfaces
mucins
76
Mucin are _____ glycoproteins
O-linked
77
Proteoglycans are core proteins _______ with many chondroitin sulfate or keratin sulfate repeats
O-linked
78
named because of their high (up to 90%) sugar content
proteoglycans
79
proteoglycans are
part of the matrix that makes up tissue structure and are found places like cartilage, dentin or predentin
80
hydrates, provide cushoning and can bind to growth factors and chemokines and cytokines
proteoglycans
81
Proteoglycans aggregate is formed around
Hyaluronic acid
82
perlecan
proteoglycan in the basement membrane
83
aggrecan
proteoglycan in knee
84
shock absorber
aggrecan
85
carbohydrate recognition domains
Lectin domains
86
protein sequences that bind sugars with hydrogen bonding
Lectin domains
87
Type of blood is dependent on the fact that you have
specific sugar sequence at end of carbohydrate chain of glycoprotein
88
Why are type O individuals prone to ulcers?
H.Pylori binds structures that resemble type ) sugars in gastric epithelium cells
89
(3) interwoven in the basement membrane
(1) Heparan sulfate
(2) collagen
(3) laminin
90
What is the big deal with Glycoproteins?
they are on cell-surface and mediate binding to to other cells, antibodies, viruses, bacteria and hormones
91
endothelial interactions with white blood cells are achieved via
endothelial cell lectin binding to the oligosaccharide chain
92
occurs when L-selectin ligans binds to L-selectin receptor on neutrophil
Rolling adhesion
93
occurs when P-selectin ligand binds to P-selectin receptor
activation and entry
94
L-selectin ligans on
endothelium
95
P-selectin ligand on
neutrophil
96
LAD II is a defect in
GDP-Fuctose transporter 1
97
neutrophils ____ and _____ the site of infection
activates and enters
98
what happens in LAD II
defect in fucosylation of glycoprotein for leukocyte binding
99
who are universal donors but cannot accept from A, B, or O
Bombay patients
100
cannot add fucose?
then you cannot make A, B, or O sugars which recognize leukocytes
101
normal cells and cancer cells express
different glycoproteins on surface
102
CAR-T or Chimeric Antigen Receptor T-Cells
engineered T-cells that recognize glycoproteins on cancer cells
103
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Dissident Georgi Markov died when someone “associated with the Bulgarian secret police” used an umbrella to fire a pellet containing ricin into his leg on a London street. Ricin is a protein poison that has two domains, one that hydrolyzes ribosomal RNA and one domain that binds cell surface galactosyl residues. What is the generic name for this latter kind of domain?
A. ABC domain
B. Lectin domain
C. Leptin domain
D. Pocket domain
E. SH2 domain
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B. Lectin domain
