Proteins Flashcards
(189 cards)
1
Q
Linear polymers of amino acids
A
Proteins
2
Q
Set of all proteins expressed by an individual cell at a particular time
A
Proteome
3
Q
3 groups that comprise the basic structure of amino acids except proline
A
Carboxyl group
Amino group
R group (distinctive side chain)
4
Q
Non polar amino acids
A
Glycine Alanine Valine Isoleucine Leucine Phenylalanine Tryptophan Methionine Proline
5
Q
Polar uncharged AAs
A
-OH
Serine
Threonin
Tyrosine
-SH
Cysteine
Amide
Asparagi e
Glutamine
6
Q
Charged AAs
A
Acidic
Aspartate
Glutamate
Basic
Arginine
Lysine
Histidine
7
Q
Group of AA that have zero net charged
Forms hydrophobic interactions
Found in the interior of protein
A
Non-polar AA
8
Q
Group of AAs that have zero net charge
Forms hydrogen bonds
Found in the surface if a protein
A
Polar uncharged AA
9
Q
Group of AA that have positive or negative net charge (acidic or basic)
Forms ionic interactions
Found in the surface of a protein
A
Charged AA
10
Q
Identify AA
has the smallest side chain
Used in the first step of heme synthesis
Used in synthesis if purines and creatine
Conjugated to bile acids, drugs, and other metabolites
Major inhibitory transmitter in the spinal cord
A
Glycine
11
Q
Identify AA
Carrier of ammonia and of carbons of pyruvate from skeletal muscle to liver
A
Alanine
12
Q
Identify AA
Together with glycine, contitutes a major fraction if free amino acids in the blood
A
Alanine
13
Q
Branched chain amino acids whose metabolites accumulate in MSUD
A
Valine
Leucine
Isoleucine
14
Q
Identify AA
Precursor of tyrosine that accumulated in PKU
A
Phenylalanine
15
Q
AA with largest side chain
A
Tryptophan
16
Q
AA precursor of niacin, serotonin, melatonin
A
Tryptophan
17
Q
AA
Source of methyl groups in metabolism
Involve in the transfer if methyl groups as S-adenosylmethionine (SAM)
A
Methionine
18
Q
AA
Precursor of homocysteine and cysteine
A
Methionine
19
Q
AA
Not an amino acid, but an imino acid
A
Proline
20
Q
AA
Contributes to the fibrous structure of collagen and interrupts alpha helices in globular proteins
A
Proline
21
Q
Uncharged polar amino acids that contain hydroxyl group
A
Serine
Threonine
Tyrosine
22
Q
AA
Site for O-linked glycosylation and phosphorylation of proteins
A
Serine
Threonine
Tyrosine
23
Q
AA precursor of thyroxine and melanin
A
Tyrosine
24
Q
Fill in
Phenylalanine—>______ —> L Dopa —> _____ —>norepinephrine —-> _____
A
Tyrosine
Dopamine
Epinephrine
25
AA
| Site for N-linked glycosylation of proteins
Asparagine
26
AA
When deaminated, it results to formation of ammonia, and is a major carrier of nitrogen to the liver from peripheral tissues
Glutamine
27
AA
| Contains sulfhydryl group that is an active part of many enzymes
Cysteine
28
AA
Participates in the biosynthesis of coenzyme A
Keratin contains a lot of its derivative
Cysteine
29
2 AA
Negatively charged at neutral pH due to the carboxylate group
Serve as proton donors
Participate in ionic interactions
Glutamate, Aspartate
30
AA
| Precursor for GABA and glutathione
Glutamate
31
Name 3 basic AA
Histidine
Arginine
Lysine
32
At neutral pH,
Arginine and lysine are (+/-) charged
Histidine, being a weak base, has ___ charge
+
| Zero
33
AA
| Precursor of histamine
Histidine
34
AA
Used in the diagnosis of folic acid deficiency (FIGlu excretion test)
Concentration in the brain varies with circadian rhythm
Histidine
35
Histidine—> (histidinase) —> FIGLU
| FIGlu —>______ —> glutamate
Tetrahydrofolate
Folate deficiency elevates urine FIGlu with oral histidine load
36
AA
| precursor of creatine, urea, and NO
Arginine
37
AA
| Precursor of carnitine
Lysine
38
21st amino acid
Selenocysteine
39
AA found in a handful of proteins, including certain peroxidases and reductases, where it participates in the catalysis of electron transfer reactions
Selenocysteine
40
A selenium ion replaces the ____ component of its structural analog, cysteine
Sulfur
41
AA that is inserted into polypeptide during translation but is not specified by a simple three-letter codon
Selenocysteine
42
Plant L alpha amino acid
Present in Lathyrus seeds
Implicated in neurolathyrism
Characterized by progressive and irreversible spastic paralysis of the lower extremities
Homoarginine and BETA ODAP
| Oxalyldiaminopropionic acid
43
Neurotoxic amino acid in cycad seeds
Beta methylaminoalanine
44
AA in cycad seeds impkicated in neurodegenerative diseases, includinf amyotropic lateral sclerosis Parkinson dementia complex in natives if Guam
Beta methylaminoalanin
45
Except for ____ all AA are chiral
Glycine
46
All amino acids in proteins are in what configuration
L configuration
47
Amino acods in bacterial cell walls and antibiotiuvs are in what configuration
D configurarion
48
Term that denotes an amino acid that bears no net charge at its isoelectric pH (pI)
Zwitterion
49
Essential amino acids
```
Phenylalanine
Valine
Tryptophan
Threonine
Isoleucine
Methionine
Histidine
Arginine
Leucine
Lysine
```
50
AA that is considered nutritionally semiessential
Arginine
51
2 AA that can be synthesized in the body, but only from essential amino acid precursors
Cystine
| Tyrosine
52
Stucture of protein determined by a protein’s amino acid sequence
Primary structure
53
_______ bonds attach the amino group of one amino to the alpha carbonyl group of another
Peptide
54
Peptide bonds have
Partial (double/single) bond character
(Rigid/non-rigid) and planar
Generally in the (cis/trans) configuration
Disrup by (what process) through prolonged exposure to a strong acid or base
Double bond
Rigid
Trans
Hydrolysis
55
Stepwise process of identifying the specific amino acid at each position in the peptide chain
Sequencing
56
2 reagents used for sequencing AA
| From N-terminal AA
Sanger’s reagent (1-fluoro-2,4-dinitribenzene)
| Edman’s reagent (phenylisothiocyanate)
57
2 Reagents used for AA sequencing
| From c-terminal amino acid
Hydralazine
| Carboxypeptidase
58
Level of protein stucture described as folding of short (3-30 residue) contiguous segments of polypeptide into geometrically ordered units
Secondary structure
59
Level of protein structure stabilized by Hydrogen bonding
Secondary
60
Secondary protein structure is stabilized by
Hydrogen bonds
61
2 forms of secondary stucture
Alpha helix
| Beta sheet
62
More common form of secondary protein structure
Alpha helix
63
Form of secondary protein structure
| Spiral, with polypeptide backbone core, with side chains extending outward
Alpha helix
64
How many AA per turn in alpha helix protein stucture
3.66
65
Alpha helix protein structure is disrupted by what
Proline, AAS with large or charged R groups
66
Keratin and hemoglobin are examples of proteins in what structure
Alpha helix (secondary structure)
Keratin (100% alpha helix)
Hemiglobin (80% alpha helix)
67
Protein structure wherein AA residues form a zigzagor pleated pattern
Beta sheet
68
In beta sheet protein stucture, R groups of adjacent residues project in (opposite/same) directions
Opposite
69
Amyloid and immunoglobulin are examples of proteins in what structure?
Beta sheet (secondary)
70
These are protein structures with less regukar configuration forming loops and bends
Non- repetitive secondary structures
71
______ are supersecondary structures produced by packing side chains from adjacent secondary structural elements close to each other
Motifs
Examples are beta-alpha-beta unit
Greek key
Beta meander
Beta barrel
72
Overall 3-dimensional shape of protein
| Includes globular and fibrous proteins
Tertiary structure
73
The assembly of secondary structural units into larger functional units such as the mature polypeptide and its component domains
Tertiary structure
74
4 bonds/interactions that stabilize tertiary protein structure
Disulfide bonds
Hydrophobic interactions
Hydrogen bonds
Ionic interactions
75
Fundamental functional and three dimensional structural units of polypeptide
Domains
76
Level of protein structure
| Number and types of polypeptide units oligomeric proteins and their spatial arrangements
Quaternary structure
77
Protein stucture that includes
monomeric vs dimeric
Homidimers vs heterodimers
Quaternary stucture
78
Specialized group of proteins required for the proper folding of many species of proteins
Prevents aggregation, paves the way for the formation of appropriate secondary structural elements and their subsequent coalescence into a molten globule
Chaperones
79
Specialized group if proteins that can rescue other proteins that have become thermodynamically trapped in a misfolded dead end by unfolding hydrophobic regions
Chaperones
80
Process that results in the unfolding and disorganization of the proteins secondary and tertiary structures
Denaturation
81
Protein stuctures destroyed by denaturation
Secondary and tertiary
82
T/F protein denaturation is accompanied by hydrolysis of peptide bonds
F
83
T/F protein denaturation may be reversibel, but most proteins remain permanently disordered
T
84
Fatal neurodegenrative diseases characterized by spongiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insoluble protein aggregates in neural cells
Prion Diseases
85
T/F prion diseases can be transmitted by protein alone, without involvement of DNA or RNA
T
86
Re Prion Dses:
An altered version of a protein converts normal protein (PrPc, rich in ______) to the pathognomonic conformation (PrPsc, rich in _____)
Alpha helices
| Beta sheets
87
Disease characterized with senile plaques and neurofibrillary tangles that contain aggregates of protein beta amyloid
Alzheimers dse
88
In Alzheimers dse, B amyloid becomes elevated, and this protein undergoes a conformational change from a soluble alpha helix rich state in beta sheets prone to self-aggregation
Alzheimer
89
Conformational transformation of protein in alzheimers dse is implicated to_____^
Apolipoprotein E
90
Examples of globular proteins
Hemoglobin
| Myoglobin
91
Hemoglobin form with low oxygen affinity
Taut form
92
Hemiglobin form with high oxygen affinity
R (relaxed) form
93
This principle states that hemoglobin binds up to 4 molecules of oxygen with increasing affinity
Positive cooperativity
94
Heme protein found exclusively in RBC
Hemoglobin
95
Heme protein present in heart and skeletal muscle
Myoglobin
96
Reservoir of oxygen
| Oxygen carrier that increase the rate of transport of oxygen within the muscle
Myoglobin
97
Myoglobin/Hemoglobin
| 1 polypeptide
Myoglobin
98
Myoglobin/Hemoglobin
| 4 polypeptides
Hemoglobin
99
Myoglobin/Hemoglobin
| Binds to 1 oxygen only
Myoglobin
100
Myoglobin/Hemoglobin
| Binds ro 4 oxygen molecules
Hemoglobin
101
Myoglobin/Hemoglobin
| Hyperbolic oxygen dissociation curve
Myoglobin
102
Myoglobin/Hemoglobin
Oxygen dissociation curve id sigmoidal
Demonstrates cooperativity
Hemoglobin
103
Myoglobin/Hemoglobin
| Oxygen storage
Myoglobin
104
Myoglobin/Hemoglobin
| Oxygen transport
Hemoglobin
105
Myoglobin/Hemoglobin
| Absent allosteric effects
Myoglobin
106
Myoglobin/Hemoglobin
| Present allosteric effects
Hemoglobin
107
Factors that shift O2-Hgb dissociation curve to the right
```
CO2
Acidity
2,3 BPG
Exercise
Temperature
```
108
Stabilizes the T structure of hemoglobin by fprming additional salt bridges that must be broken prior to conversion to the R state
2, 3 BPG
109
T/F
| In infants, 2,3 BPG binds more weakly to HbF than to HbA. Hence, HbF has higher affinity to oxygen than HbA
T
110
T/F
Prolonged exposure to high altitude increases the number of erythrocytes. Hence, increased hemoglobin and increased BPG lowers the affinity of HbA for 02
T
111
A low pO2 in peripheral tissues (promotes/inhibits) the synthesis in erythrocytes of 2,3 BPG from the glycolytic intermediate 1,3 BPG
Promotes
112
This effect describes that the release of oxygen from hemoglobin is increased when the pH is lowered or when the hemoglobin is in the presence of increased pCO2
BOHR effect
113
T/F
| Oxyhemoglobin has greater affinity for protons than does deoxy form
F
114
The effect of changes in hemoglobin saturation on the relationship of CO2 content to PCO2
Haldane effect
115
Minor type of hemoglobin
| Produced from conception to first few months
Embryonal hemoglobin
| Hb Gower 1
116
Hb Gower 1
| (Embryonal Hemoglobin) is synthesized where?
Yolk Sac
117
Identify minor hemoglobin
| Alpha2gamma2
Fetal hemoglobin
| HbF
118
Minor Hgb synthesized first few months to after birth
HbF (Fetal Hgb)
119
Minor Hgb synthesized in the liver
HbF (Fetal Hemoglobin)
120
Minor hgb with alpha2 beta 2 chains
HbA
| Hemoglobin A
121
Minor hemoglobin synthesized 8 months and onwards
HbA
122
Minor hemoglobin synthesized in marrow
HbA and HbA2
123
Minor Hgb
| Alpha2 delta 2
HbA2
124
Minor Hgb synthesized shortly after birth onwards
HbA2
125
Site if synthesis of HbA2
Marrow
126
Major Hgb found in fetus
| Has increased affinity doe oxygen than HbA
Fetal Hgb
| HbF
127
Hgb with 2 alpha and 2 delta chains
HbA2
128
Comprises 2% of total adult Hgb
HbA2
129
HbA1C forms when glucose enters RBC and glycates_____ residues and the amino terminals of Hgb
Epsilon amino group of lysine
130
Based on ADA recommendations, cutoff of HbA1C for the diagnosis of diabetes is >/=____
6.5 %
131
Lowering A1C to below ___% has been shown to reduce micrivascular and neuropathic complications of type 1 and type 2 DM
7
132
Form of Hgb bound to carbon monoxide in place of oxygen
| Hb becomes cherry pink in color
Carboxyhemoglobin
133
CO has ___ times greater afficnitu for Hgb than oxygen
200
134
Oxidized form of Hgb (Fe3+) that does nor bind oxygen as readily but has increased affinity for cyanide
Methemoglobin
135
Chocolate cyanosis, O2 saturation is at 85%
| Anxiety, headache, dyspnea
Methemoglobinemia
136
Treatment for methemoglobinemia
Methylene blue or ascorbic acid (both reducing agents)
137
Treatment for acute massive methemoglobinemia due to ingestion of chemicals
IV methylene blue
138
Disorder characterized by an inherited defect in the RBC membrane that renders the erythrocytes spheroidal, less deformable , and vulnerable to splenic sequestration
Hereditary spherocytosis
139
Mutation in what protein is most commonly implicated in hereditary spherocytosis
Ankyrin
Others:
Spectrin
Band 4.1
Band 3
140
Diagnostic method for hereditary spherocytosis
Osmotic fragility test
141
Treatment for symptomatic hereditary spherocytosis
Splenectomy
142
Disease that results from point mutation in both genes coding for the beta chain that results to
Glutamine—>valine
Sickle cell dse
143
Polymerization and decreased solubility of the deoxy form of Hb
Distortion of the RBC membrane
Misshapen, rigid RBCs that occlude capillaries
Sickle cell dse
144
Anemia
Splenomegaly
Jaundice
Hereditary spherocytosis
145
Anemia
Tissue anoxia
Painful crises
Protective against malaria
Sickle cell dse
146
Treatment for sickle cell dse
```
Hydration
Analgesics
Antibiotics if with infection
Transfusions
Hydroxyurea
```
147
Hemoglobin variant that has a single amino acid substitution in 6th position of the beta globin chain, in which glutamate—->lysine
Hemoglobin C
148
In hemoglobin C disease,
| Glutamate —-> _____
Lysine
149
T/F patients with Hgb C present with severe hemolytic anemia
F
| Mild
150
T/F
| No specific therapy is required for Hgb C
T
151
Inadequate synthesis of alpha chains
Anemia
Acumulation of Hb Bart (gamma 4) and Hb H (beta 4), and Beta chain precipitation
Alpha thalassemia
152
In alpha thalassemia, symptoms appear at birth
| T/F
T
| because alpha chains are needed for HbF and HbA
153
Silent carrier—>_____—>HbH disease —>Hydrops fetalis
Alpha thalassemia trait
154
Inadequate synthesis of beta chains
Anemia
Accumulation if Hb Barts
And alpha chain precipitation
Beta thalassemia
155
T/F symptoms of beta thalassemia appear only AFTER birth
T
156
2 examples of fobrous proteins
Collagen
| Elastin
157
Most abundant protein in the body
Collagen
158
Collagen structure is stabilized by ____ bonds
Hydrogen
159
A long stiff extracellular structure in which 3 polypeptides (a chains) each 1000 AA in length are wound around ine another in a triple helix
Collagen
160
Most common form of collagen
Type I
161
Collagen is rich in what 2 AA
Proline
| Glycine
162
Facilitates kinking of the collagen structure
Proline
163
Type of collagen found in BONE, skin, tendond, dentin, fascia, cornea, late wound repair
I
164
Type of collagen found in CARTILAGE (including hyaline), vitreous body, nucleus pulposus
II
165
Type of collagen found in RETICULIN, skin, blood vessels, uterus, fetal tissues, granulation tissue
III
166
Type of collagen found in basemend membrane or basal lamina
Type IV
167
Type of collagen beneath stratified squamous epithelium
Type 7
168
Inherited disorder
Hyperextensibility of skin
Abnormal tissue fragility
Increased joint mobility
Ehlers Danlos Syndrome
169
```
Subtype of Ehlers Danlos
Defect in Type I and Type V collagen
Joint hypermobility
Severe skin abnormalities
Less severe joint changes
```
Classical
170
```
Subtype of Ehlers Danlos
Defect in Type III collagen
Joint hypermobility
Skin abn
Sever joint pain
Most common subtype
```
Hypermobility
171
Ehlers Danlos Subtype
Type III
Fragile blood vessels and organs, small stature, thin and transluscent skin, easy bruising
Increased risk for intracranial aneurysms
Most serious
Vascular
172
Multiple fractures
Blue sclerae
Hearinf loss
Dental imperfections
Osteogenesis imperfecta
173
Most common form of osteogenesis imperfecta is autosomal _____ with abnormal collagen type ____
Dominant
| Type I
174
Main presenting sign of Alport syndrome
Hematuria
175
Hematuria
Ocular lesions
Hearing loss
End stage renal dse
Alport syndrome
176
Alport syndrome is defect in what type of collagen
IV
177
Skin breaks and blisters
| Defect in type VII collagen, which anchors the basal lamina to collagen fibrils in the dermis
Epidermolysis bullosa
178
Sore spongy gums
Loose teeth
Poor wound healing
Petechiae on skin and mucous membrane
Scurvy
179
Deficiency of this vitamin causes decreased cross linking of collagen fibers
Vitamin C
180
Hydroxylation of collagen is a post-transcriptional modification requiring _______
Ascorbic acid
181
Kinky hair and growth retardation
| Dietary deficiency of copper required by lysyl oxidase
Menke’s disease
182
Menkes dse reflects a dietary deficiency of copper required by _____
Lysyl oxidase
183
Tissues that contain elastin
```
Lungs
Large arteries
Elastic ligaments
Vocal cords
Ligamentum flavum
```
184
______, precursor of elastin, is deposited into irregular fibrillin scaffold cross-linked by _____
Tropoelastin
| Desmosine
185
Marfan syndrome is caused by mutation by ______ gene
Fibrillin
186
```
Taller and thinner than family members
Dolichostenomelia
Arachnodactyly
Aortic dilatation and dissection
Upward dislocation of lens (ectopia lentis)
```
Marfan syndrome
187
Airtic dilatation occurs in __ % of patients with Marfan syndrome
70-80
188
Deficiency inhibits proteolytic enzymes from hydrolyzing and destroying proteins
Alpha 1 antitrypsin
189
```
Liver disease (cirrhosis and HCC)
Emphysema (due to alveolar wall destruction by elastase)
```
Alpha 1 antitrypsin deficiency
