Structures of Amino Acids and Proteins Flashcards
(116 cards)
1
Q
Most abundant organic molecule in the HUMAN BODY
A
Proteins
2
Q
Enantiomer of amino acids
seen in the human body
A
L-isomer
3
Q
An imino acid
A
Proline
4
Q
AA with the smallest side chain, only achiral amino acid among the 20 AAs; Used in the first step of heme
synthesis (formation of d-ALA)
A
Glycine
5
Q
Accumulated AAs in maple
syrup urine disease (MSUD)
A
Branch-chained AAs
Valine
Leucine
Isoleucine
*deficient enzyme in MSUD is branched-chain alpha-keto acid dehydrogenase
6
Q
AA with the largest side chain
A
Tryptophan
7
Q
Known as the 21st AA
A
Selenocysteine
*A cysteine that instead of having sulfur, has selenium
*a catalysis of electron transfer reactions (ETC)
8
Q
Known as the 22nd AA; restricted only in some methanogenic archaea and bacteria
A
Pyrrolysine
*creates methane
9
Q
Only semi-essential AA
A
Arginine
10
Q
Sulfur-containing amino acids
A
Cysteine
Methionine
11
Q
AAs with aromatic structures
(benzene rings)
A
Phenylalanine
Tyrosine
Tryptophan
Histidine
12
Q
Most basic AA
A
Arginine
13
Q
Most acidic AA
A
Aspartic acid
14
Q
First ever sequenced protein
A
Insulin
15
Q
First discovered hormone
A
Secretin
16
Q
Most common secondary structure
A
Alpha-helix
17
Q
Secondary structure seen in
abnormal prion protein (PrP
Sc) and Alzheimer disease
histopathology
A
Beta-sheets
18
Q
AAs that can disrupt the
alpha-helix structure
A
Proline
Glycine
19
Q
The only structure of
proteins not affected by
denaturation
A
Primary structure
20
Q
Reading of amino acid
sequences; Order of amino
acid sequence synthesis
A
From N-terminus (NH3 end)
to
C-terminus (COOH end)
21
Q
Amino acid terminus
containing targeting signals
A
N-terminus
22
Q
Amino acid terminus
containing retention signals
A
C-terminus
23
Q
Amino acid terminus
allowing protein to be
inserted into a membrane
without having a
transmembrane domain
A
C-terminus
24
Q
Number of pyrrole rings in a
porphyrin
A
Four
25
Structure of pyrrole rings
Aromatic structure
26
Bridge formed between
pyrrole rings in a porphyrin
Methenyl or methyne
bridges
27
Maximum absorption
spectrum of porphyrins
400 nm (known as the Soret peak)
28
Heme is a metalloporphyrin
containing this metal
Iron
*also has histidine
29
Amino acid serving as the
biosynthetic precursor to
porphyrins
Glycine
30
Most common form of
hemoglobin after birth
Hemoglobin A1
31
Location of alpha-globin
genes
Chromosome 16 (4 alleles)
Alpha thalassemia
1 missing - silent carrier
2 missing - alpha thalassemia trait
3 missing - HbH disease (B4)
4 missing - Hydrops fetalis (y4)
32
Location of beta-globin genes
Chromosome 11 (2 alleles)
Beta thalassemia
1 missing - minor - mild anemia
2 missing - major - moderate/severe anemia
33
Defect in sickle cell disease
Glutamate → Valine at the
6th position of the betaglobin
*Polar charged (acidic) AA turns into a nonpolar AA --> disorganization of protein --> hemolytic anemia
*Tx: Hydroxyurea --> ↑ HbF
34
Defect in hemoglobin C disease
Glutamate → Lysine at the
6th position of the β-globin
*Polar charged (acidic) AA turns into a polar charged (basic) AA --> mild hemolytic anemia
35
Hemoglobin Bart
composition
4 gamma-globin
36
Hemoglobin H composition
4 beta-globin
37
Oxygen dissociation curve of
myoglobin
Hyperbolic
38
Oxygen dissociation curve of
hemoglobin
Sigmoidal
39
Most abundant protein in the
body
Collagen
40
Most common form of
collagen in the body
Type I collagen
41
Type of collagen present in
early wound repair
Type III collagen
42
Type of collagen in late
wound repair
Type I collagen
43
Defective step of collagen
synthesis encountered in
scurvy
Hydroxylation step
44
Defective step of collagen
synthesis encountered in
osteogenesis imperfecta
Formation of triple helix
*blue sclerae
45
Defective step of collagen
synthesis encountered in
Menkes disease
Cross-linking step
(dysfunction in copper requiring
lysyl oxidase)
46
Most common form of
Ehlers-Danlos syndrome
(EDS)
Hypermobility EDS
47
Most serious form of EDS
Vascular EDS
48
Most common type of
collagen affected in EDS
Type III collagen
49
Defective type of collagen in
dystrophic epidermolysis bullosa
(DEB)
Type VII collagen
50
Defective structure in Marfan
syndrome
Fibrillin
51
Triad of Marfan syndrome
Skeletal changes
Aortic dilatation, dissestion
Upward and outward
dislocation of the lens
(vs downward and inward
dislocation of the lens in
homocystinuria)
52
Main cell that synthesizes
antibodies or Igs
Plasma cells
(derived from B cells)
53
Fragment of Ig containing the
antigen-binding site
Fab
*contains both light and heavy chains
*contains variable and constant regions
54
Fragment of Ig containing the
complement-binding site and
macrophage-binding site
Fc
*contains heavy chains only
*contains constant region only
*determine isotype
55
Responsible for determining
the isotype of class of Ig
Heavy chains
56
Most abundant light chain in
humans
Kappa chain
57
Proteins containing light
chains (lambda and kappa chains) and can be found in
the urine of patients with
multiple myeloma
Bence-Jones protein
58
Most abundant Ig in the
BODY (which includes mucous
membranes)
IgA
59
Most abundant Ig in SERUM
IgG > IgA > IgM > IgD > IgE (GAMDE)
60
Cleaves Ig into 3 parts
Papain
*2 separate Fab fragments
*1 Fc fragment
61
Cleaves Ig into 2 parts
Pepsin
*1 bivalent Fab fragment
*1 Fc fragment
62
Refers to the part of the
ANTIGEN to which an antibody
binds
Epitope
63
Refers to the part of the
ANTIBODY that binds to the
epitope of the antigen
Paratope
64
Configuration of amino acids in human proteins
L-configuration AA
*D-configuration AA -bacterial cell walls
*If sugar, most common in humans is D-configuration
65
Amino acid which bear no net charge at isoelectric pH
Zwitterion
66
In an amino acid, carboxyl group is the _________ while amino group is the _________. At physiologic pH, carboxyl group is __________ while amino group is __________
Acid
Base
Deprotonated (COO- na lang from COOH)
Protonated (NH3 na from NH2)
67
What are the nonpolar amino acids?
GAVIL, Pray To Mary Pirst!
Glycine
Alanine
Valine
Isoleucine
Leucine
Phenylalanine
Tryptophan
Methionine
Proline
68
What are the polar uncharged amino acids?
W/ hydroxyl group (-OH)
Hi Sir Threo Tyrone!
Serine
Threonine
Tyrosine
W/ sulfhydryl group (-SH)
Cysteine
W/ amide group
Asparagine
Glutamine
69
What are the polar charged amino acids?
ACIDIC
Aspartate/Aspartic acid
Glutamate/Glutamic acid
BASIC
Arginine
Lysine
Histidine
70
Carrier of ammonia and of the carbons of pyruvate from skeletal muscle —> liver
Alanine
71
AAs important for ammonia disposal in body
Alanine
Glutamine
Glutamate
72
AA that serves as Precursor of tyrosine and monoamines
Phenylalanine
Phenylalanine derivatives: “Pare, True Love Does Not Exist”
Tyrosine—>L-dopa—>Dopamine—>Norepinephrine—>Epinephrine
*Phenylalanine accumulation (phenylalanine hydroxylase deficiency) causes Phenylketonuria (mousy odor)
73
Tryptophan derivatives
TRYp Mo Siya No?
Melatonin
Serotonin
Niacin
74
Methionine derivatives
Homocysteine
Cysteine
*methionine also source for methyl groups in metabolism (transfer of methyl groups as S-adenosylmethionine)
75
Sites for O-linked glycosylation and phosphorylation of proteins
Serine, Threonine, Tyrosine
76
Tyrosine derivatives
Thyroxine
Melanin
L-Dopa
Dopamine
Norepinephrine
Epinephrine
77
Site of N-linked glycosylation of proteins
Asparagine
78
79
Deaminated leading to formation of ammonia; also the major carrier of nitrogen from peripheral tissues to liver
Glutamine (deaminated by glutaminase)
80
Curly/kinky hair is caused by?
Disulfide bonds formed by cystine residues
*disruption if disulfide bonds (heat) may straighten hair temporarily
*Keratin contains a lot of cysteine; people with curly hair have more cystine
81
Derivatives of Glutamate
GABA
Glutathione
82
Among the basic amino acids, at neutral, who are positively charged and who dont have charge?
Positively charged - Arginine, Lysine
No charge - Histidine
83
Derivative of Histidine
Histamine
84
Derivatives of Arginine
Urea, Creatinine, Citrulline, Nitric Oxide
85
Derivative of Lysine
Carnitine
86
ESSENTIAL AMINO ACIDS
PVT TIM HALL, always ARGues, never TYRes
Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Histidine
Arginine (Semi-essential)
Leucine
Lysine
87
Denaturation can destroy other protein structures except
Peptide bonds (can only be destroyed by hydrolysis)
88
Oxygen binds to hgb if hgb is in the ____________ form and its iron is in the ______________ form
R “relaxed” form
Fe2+/ferrous
*taut form (low o2 affinity) = deoxyhgb
*relaxed form (high o2 affinity) = oxyhgb
89
BONDS PRESENT IN:
1. Primary structure
2. Secondary structure
3. Tertiary structure
4. Quaternary structure
1. Peptide bonds (2D)
2. Peptide bonds + hydrogen bonds (2D)
3. Peptide bonds + hydrogen bonds + disulfide bonds + hydrophobic bonds + ionic interaction (3D)
4. Peptide bonds + hydrogen bonds + disulfide bonds + hydrophobic bonds + ionic interaction (3D)
90
Stabilizes T structure of hgb. Inc synthesis in low PO2 in peripheral tissues
2,3-Bisphosphoglycerate (2,3-BPG)
91
When glucose enters the erythrocytes, it glycates the __________________ and _______________________
E-amino group of lysine residues
Amino terminals of hgb
92
First biomarker that rises during MI
Myoglobin
93
Cherry red skin discoloration
Cause and treatment
Carbon monoxide poisoning (carboxyhgb)
100% O2 therapy
94
Chocolate cyanosis
Cause and treatment
Methemoglobin (presence of ferric state (Fe3+)) aka Cyanide poisoning
Oral methylene blue, ascorbic acid
IV methylene blue
95
Greenish discoloration
Cause and treatment
Forms when sulfur irreversibly binds to heme molecule --> unable to carry O2 (sulfhemoglobin - from sulfa containing drugs)
96
Intrinsic defect in RBC: ankyrin, spectrin, band 3 and 4.1 --> less deformable RBCs
Hereditary spherocytosis
*dx: osmotic fragility test
*mgt: splenectomy (symptomatic relief)
97
Collagen is a long stiff extracellular structure in which ________________________________________. It is synthesized by _______________________
3 polypeptides (a-chains) are wound around one another in a triple helix;
Fibroblasts (osteoblasts, chondroblasts)
98
Steps of collagen synthesis
RER
1. Synthesis of preprocollagen; Preprocollagen
2. Hydroxylation of proline and lysine residues; Procollagen
3. Glycolysation of hydroxylysine --> formation of triple helix; Procollagen (in triple helix)
ECF
4. Exocytosis of procollagen; Procollagen in triple helix)
5. Proteolytic processing (cleavage of C and N terminus); Tropocollagen (insoluble in water, in triple helix)
6. Cross linking of tropocollagen via lysyl oxidase; Collagen fiber
99
Required materials in Step 2 of collagen synthesis (hydroxylation of proline and lysine residues)
Vitamin C
Ferrous iron (Fe2+)
Oxygen
Alpha-ketoglutarate
100
Required materials in Step 6 of collagen synthesis (cross-linking of tropocollagen via lysyl hydroxylase)
Copper - needed by lysyl hydroxylase
101
TYPES OF COLLAGEN
Disease: Osteogenesis Imperfecta
Type?
Distribution in body?
Type I
Bone, tendon, late wound repair (bONE, tendONE)
102
TYPES OF COLLAGEN
Disease: Achondrogenesis
Type?
Distribution in body?
Type II
Cartilage (car-TWO-lage)
103
TYPES OF COLLAGEN
Disease: Ehlers-Danlos Syndrome (vascular)
Type?
Distribution in body?
Type III
Reticulin, skin, blood vessels, granulation tissue, early wound repair (THREE-ticulin)
104
TYPES OF COLLAGEN
Disease: Alport syndrome; Goodpasture syndrome
Type?
Distribution in body?
Type IV
Basement membrane [Under the floor (FOUR)]
105
TYPES OF COLLAGEN
Disease: Ehlers-Danlos syndrome (classic)
Type?
Distribution in body?
Type V
Bone, skin, fetal tissue, placenta
106
TYPES OF COLLAGEN
Disease: Dystrophic epidermolysis bullosa
Type?
Distribution in body?
Type VII
Anchoring fibrils (look like hooks that look like 7)
107
A condition due to defect in Type IV collagen that manifests as Gross hematuria, ocular lesions, hearing loss
Alport syndrome (X-linked, genetic)
108
A condition due to defect in Type IV collagen that manifests as Gross hematuria and hemoptysis
Goodpasture syndrome (Anti-GBM ab, autoimmune)
109
Corkscrew hair
Scurvy - Vitamin C deficiency
110
Kinky or steely hair
Menkes disease - Copper deficiency
111
Major amino acids of elastin
Proline
Lysine
112
Protein that forms the template of elastic fiber formation
Fibrillin
113
Structures that cross link the precursor tropoelastin fibers together
Desmosine
114
The constant region of Ig is toward the _________________________ (carboxyl/amino) end
Carboxyl
115
The variable region of Ig is toward the _________________________ (carboxyl/amino) end
Amino
116
Confers flexibility and allow both Fab arms to move independently for binding to antigen
Hinge region
