Amino Acids, Proteins, and Analytical Methods Flashcards
(151 cards)
1
Q
Amino acids may have a positive, negative, or neutral charges, depending on the ____
A
pH
2
Q
Means that amino acids contain both acidic and basic groups
A
Amphoteric (zwitterion)
3
Q
pH > 7.4, when a base is added to the amino acid resulting molecule has a ____ charge
A
Negative
4
Q
pH = 7.4, internal transfer of a hydrogen ion from teh -COOH group the -NH2 group results in a ____ charge
A
Neutral
5
Q
pH < 7.4, when an acid is added
A
Positive
6
Q
Defined as the pH at which net charge is zero; i.e., there are equal numbers of positive and negative charges
A
Isoelectric point
7
Q
If pH > pI
A
Amino acid has a negative charge
8
Q
If pH < pI
A
Amino acid has a positive charge
9
Q
Proteins act in vivo as ____ ____ due to their acid-base properties
A
mild buffer
10
Q
Essential amino acids
A
Leucine, isoleucine, valine, methionine, tryptophan, phenylalanine, threonine, lysine
11
Q
Formed when the alpha amino group of one amino acid is covalently linked w/ the alpha-carboxyl group of a second amino acid
A
Peptide bond
12
Q
The formation of glucose from non-CHO sources, such as amino acids, glycerol, or fatty acids
A
Gluconeogenesis
13
Q
Starting and ending products of gluconeogenesis
A
Starting: amino acids/glycerol/ fatty acids
Ending: glucose
14
Q
The process of amino group removal or transfer to make different amino acids
A
Transamination
15
Q
Starting and ending products of transamination (2 of them)
A
Starting: glutamic acid/oxaloacetate
Ending: alanine/aspartate
16
Q
The removal of the amino group, forming toxic ammonia
A
Deamination
17
Q
Starting and ending products of deamination
A
Starting: ammonia
Ending: urea
18
Q
Organ in which the metabolic/catabolic pathways occur in the body
A
Liver
19
Q
Occurs when the plasma levels of the amino acid are normal, but the renal reabsorptive mechanism is defective
A
Renal aminoaciduria
20
Q
____ plasma levels and ____ urine levels of amino acids in renal aminoaciduria
A
normal; increased
21
Q
Defect in renal tubular reabsorption of cystine, ornithine, lysine, and arginine; most common error of amino acid transport
A
Cystinuria
22
Q
Three primary renal aminoacidurias
A
Cystinuria, Hartnup disease, and Fanconi syndrome
23
Q
Prone to renal calculi of cystine; cystine crystals on urine microscopic
A
Lab findings in cystinuria
24
Q
Increased urinary excretion of neutral monocarboxylic amino acids
A
Hartnup disease
25
Patients have a nicotinamide (vit B) deficiency, so they can have pellagra (red, scaly rash), plus neurological muscular abnormalities
Clinical features of Hartnup disease
26
Renal dysfunction of the proximal convoluted tubule
Fanconi Syndrome
27
Polyuria, dehydration, hypokalemia, acidosis, osteomalacia, cannot reabsorb necessary nutrients, bowing of the legs, low weight/height, abdominal distention, enlargement in wrist and ankle joints all indicate \_\_\_\_
Clinical features of Fanconi syndrome
28
Plasma level of one or more amino acids exceeds the renal threshold
Overflow aminoaciduria
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\_\_\_\_ plasma levels and ____ urine levels of amino acids in overal aminoaciduria
increased; increased
30
Due to a deficiency or absence of phenylalanine hydroxylase enzyme
Phenylketonuria (PKU)
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Spastic movements and seizures, sever mental retardation if untreated, eczema, feeding difficulties, vomiting, delayed mental/social development, hypopigmentation, Increased serum phenylalanine, Decreased serum tyrosine, increased urine phenylpyruvic acid
Clinical features of PKU
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Due to fumarylacetoacetase deficiency
Type I tyrosinemia
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Causes cirrhosis and renal damage leading to Fanconi syndrome, elevated serum and urine tyrosine levels, elevated methionine in serum
Clinical features of Type I tyrosinemia
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Due to tyrosine aminotransferase deficiency
Type II tyrosinemia
35
Skin lesions, ocular abnormalities (corneal dystrophy), elevated serum and urine levels of tyrosine, tyrosine crystals in urine, serium methionine NOT increased
Clinical features of type II tyrosinemia
36
Due to 4-hydroxyphenylpyruvate dioxygenase deficiency
Type III tyrosinemia
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Mild mental retardation, seizures, periodic loss of balance and coordination, increased serum tyrosine
Type III tyrosinemia
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Caused by a defect in the enzyme homogentisic acid oxidase
Alkaptonuria
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Homogentisic acid increases in serum and urine, urine turns brown/black when exposed to light and air or when alkali is added, ocular ochronosis
Clinical features of alkaptonuria
40
Most commonly caused by a defect of CBS (cystathionine beta synthase)
Homocystinuria
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Both methionine and homocystine are increased in serum and urine, ocular (lens displacement) and skeletal abnormalities (knock knee), cardiovascular problems (thromboli due to sticky platelets), pigeon chest
Clinical features of homocystinuria
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Due to a defect in the enzyme alpha-ketoacid decarboxylase; also known as branched chain aminoaciduria due to excretion of the branched chain amino acids valine, leucine, and isoleucine
Maple Syrup Urine Disease (MSUD)
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Hypoglycemia, ketacidosis (in blood and urine), lethargy, poor appetite, vomiting, convulsions, detected by the 11th day of life, maple syrup odor, increased ketone bodies
Clinical features of MSUD
44
Amino acids can be measured using 3 screening methods
Thin layer chromatography (TLC), photometric screening test, and Guthrie test
45
3 quantitative tests for the presence of aminoacidurias
Ion exchange chromatography, gas liquid chromatography (GLC), and high performance liquid chromatography (HPLC)
46
Four protein structures
Primary
Secondary
Tertiary
Quaternary
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Specific sequence of amino acids
Primary structure
48
Uniting of several protein units or a protein plus another structure
Quaternary structure
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Folding of a chain into a compact 3D conformation w/ a specific shape; confers specific biological properties
Tertiary structure
50
Recurring spatial arrangement of amino acids in 3D space
Secondary structure
51
Protein denaturation disrupts the bonds that hold \_\_\_\_, \_\_\_\_, and ____ structures together
Secondary, tertiary, and quaternary
52
What is happening when proteins lose their biological function?
Denaturation
53
4 processes that can denature proteins
1. Extreme temperatures
2. pH change
3. Detergents, metals, organic solvents
4. Mechanical mixing
54
8 biological functions of proteins
1. Transport
2. Cellular receptors
3. Catalysis
4. Structure
5. Nutrition
6. Maintenance of oncotic pressure
7. Host defense
8. Hormonal
55
Definition of "acute phase reactant" (APR)
Proteins that increase or decrease in response to an acute phase (inflammation, infection, myocardial infarction, tumor, surgery, trauma, etc.)
56
List 3 negative APRs
Transthyretin (prealbumin), albumin, transferrin
57
What is the importance of the different solubility characteristics of albumin and globulins?
Albumin is water-soluble
Globulins are water-insoluble
58
3 examples of fibrous proteins
1. Collagen
2. Elasin
3. Keratin
59
Definition of nitrogen balance
Equals an equilibrium b/w intake and output
60
6 examples of conjugated proteins
1. Nucleoproteins
2. Mucoproteins
3. Glycoproteins
4. Lipoproteins
5. Metalloproteins
6. Phosphoproteins
61
What is positive nitrogen balance?
When intake \> output
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How does positive nitrogen balance impact patient health?
It's associated w/ general good health especially important in growing children, pregnant women, and body builders
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What is negative nitrogen balance?
When output \> intake
64
How does negative nitrogen balance impact patient health?
It's seen in metastic cancer, severe infections, trauma, surgery, burns, and starvation
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2 names for the plasma protein commonly analyzed for nitrogen balance assessment
Transthyretin or prealbumin
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Hyperproteinemia caused by _RELATIVE_ changes
1. inadequate water intake
2. Excessive water loss (severe vomiting, diarrhea)
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Two _GENERAL_ processes which may cause total protein abnormalities
1. Relative (apparent) change due to changes in water volume
2. True (absolute) change
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Hyperproteinemia caused by _ABSOLUTE_ changes
1. Increased production (malignancy, such as multiple myeloma)
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Hypoproteinemia caused by _RELATIVE_ changes
1. Increased plasma water volume (water intoxication, massive IV infusion, salt retention syndromes)
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Hypoproteinemia caused by _ABSOLUTE_ changes
1. Increased loss (end-stage renal disease, such as nephrotic syndrome; severe blood loss; trauma; severe burns)
2. Low protein intake or starvation
3. Decreased production (liver disease)
71
Definition of hemodilution
Increase in body water, causing an apparent decrease in plasma protein concentration
72
Define hemoconcentration
Decrease in body water, causing an apparent increase in plasma protein concentration
73
Function of albumin
1. Transport of water-insoluble compounds
2. Maintenance of colloid osmotic pressure
74
Function of transthyretin (prealbumin)
1. Indicator of nutritional status along w/ retinol binding protein (RBP)
2. Transports thyroid hormones and retinol
75
Albumin reference range (make sure to know units)
3.5--5.0 g/dL
76
Hypoalbuminemia
- 3 general causes
1. Decreased production
2. Decreased intake
3. Increased loss
77
4 examples of globular proteins
1. Albumin
2. Globulins
3. Histones
4. Protamine
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Causes for decreased production in hypoalbuminemia
1. Liver disease
2. Hereditary analbuminemia (rare)
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Causes for decreased intake in hypoalbuminemia
1. GI disease
2. Starvation
80
Causes for increased loss in hypoalbumenia
1. Renal disease
2. Severe burns
81
Names of 3 plasma proteins in alpha1-globulins
1. alpha1 antitrypsin
2. alpha1 acid glycoprotein
3. alpha1 fetoprotein
82
Functions of alpha1 antitrypsin
To inactivate protease enzymes (elastase, collagenase)
83
Low levels of alpha1 antitrypsin is associated w/ what disease? High levels?
Low: juvenile-onset cirrhosis and emphysema due to M-protein deficiency
High: stress states
84
Functions of alpha1 acid glycoprotein
To inactivate progesterone
85
Alpha1 acid glycoprotein
- Increased in what?
- Decreased in what?
Increased in stress, rheumatoid arthritis, SLE (lupus), and Crohn's disease
Decreased in malnutrition, severe liver damage, protien loss (GI and renal)
86
Source of elevated alpha1 fetoprotein levels?
Synthesized in fetal liver and peaks in second trimester of pregnancy
87
Alpha1 fetoprotein
- Prenatal marker for neural tube defects increased in?
- Prenatal marker decreased in?
- Increased in spina bifida, anacephaly
- Decreased in Down Syndrome
88
List the 3 alpha2 globulins
1. Haptoglobin
2. Alpha2 macroglobulin
3. Ceruloplasmin
89
Function of haptoglobin
Binds to free hemoglobin in plasma in a ratio of 1 haptoglobin to 2 hemoglobins and transports it to RES to be degraded
90
When is haptoglobin decreased?
Decreased in hemolytic anemia b/c it's busy binding hemoglobin up
91
Function of alpha2 macroglobulin
Functions as a protease inhibitor (trypsin, chymotrypsin, thrombin, etc.)
92
Alpha2 macroglobulin is increased in what?
Increased in nephrotic syndrome
93
Function of ceruloplasmin
Functions as a copper transporting protein
94
Ceruloplasmin is increased in what? (5)
1. Infections
2. Malignancy
3. Hodgkin's disease
4. Acute leukemia
5. Rheumatoid arthritis
95
Name the four beta globulins
1. Transferrin
2. Beta2 microglobulin
3. Hemopexin
4. C-reactive protein
96
Function of transferrin
Functions to transport iron (and copper)
97
Why is transferrin measured?
To diagnose and monitor iron deficiency anemia
98
Transferrin
- Increased in what?
- Decreased in what?
increased in iron-deficiency anemia and pregnancy
Decreased in acute phase or protein-losing conditions
99
Function of beta2 microglobulin
??
100
Why is beta2 microglobulin measured?
To assess renal tubular function as it is small enough to be filtered by kidney
101
Beta2 microglobulin
- Increased in what?
- Decreased in what?
Increased in neoplasm, especially those associated w/ B-lymphocytes
Decreased??
102
Function of hemopexin
Binds heme after hemoglobin breakdown
- Acts like a backup to haptoglobin
103
What is the C-reactive protein?
Very sensitive but non-specific marker for systemic inflammation
104
C-reactive protein
- Elevated in what?
Elevated in persons w/ cardiovascular disease; strong predictor of future coronary events
105
What are the relative risk categories for heart disease based on CRP predictions?
1. Low risk
2. Average risk
3. High risk
106
What are the functions of gamma globulins?
To respond to antigenic stimuli to recognize, destroy, and eliminate Ags
107
Function of IgG
Functions as a major anti-viral and antibacterial Ab
108
Functions of IgA
Functions to provide external surface protection against microorganisms
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Functions of IgM
Functions as the first immunoglobulin produced during an immune response
110
Functions of IgD
May play a role in the activation of B-lymphocytes
111
Functions of IgE
Associated w/ allergic (atopic) reactions (asthma, anaphylaxis, etc.)
112
Clinical symptoms for multiple myeloma
Bone pain, punched out lesions on bone X-ray
113
Lab findings associated w/ multiple myeloma
- Plasma proteins increased (10-12)
- Paraproteins present
- Hyperviscosity of plasma
- Bence-Jones protein in urine
- 50% have increased IgG; 25% have increased IgA
114
Specific source of paraprotein in multiple myeloma
malignant neoplasm involving a single clone of plasma cells
115
Clinical symptoms for Waldenstom's macroglobulinemia
??
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Lab findings associated w/ Waldenstom's macroglobulinemia
- increase in IgM from mature B-lymphocytes
- Plasma hyperviscosity
- 80% have Bence-Jones protein in urine
- Rouleaux and plasmcytoid lymphs
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Specific source of paraprotein in Waldenstom's macroglobulinemia
Arise from lymphoid tumors (lymphomas or chronic lymphocytic leukemia)
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Monoclonal gammopathy
Increase in one type of immunoglobulin only
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Polyclonal gammopathy
- Due to infection
- Increase in IgG in autoimmune response
- Increase in IgA in skin, respiratory, or renal infections
- Increase in IgM in viral infections or malaria
120
Hypogammaglobulinemia
- Lack of one or more immunoglobulins due to B-lymphocyte malfunction
- Highly susceptible to bacterial infections
- Treat w/ IV immunoglobulins
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Agammaglobulinemia
- Due to genetic defect
- Decrease of IgG
- Recurrent infections
- Treat w/ immunoglobulins, antibiotics, BMT
122
Plasma protein reference range (make sure to know the units)
6.4--8.3 g/dL
123
Ceruplasmin
- Decreased in what (3)?
1. Wilson's disease
2. Malnutrition
3. Chronic hepatitis
124
Reference range for total protein (make sure to know units)
6.8--8.3 g/dL
125
Reference range for albumin (make sure to know units)
3.4--5.0 g/dL
126
This analytic method is based on quantitation of the nitrogen content of proteins
- Nitrogen content x 6.25 to obtain total protein value
Kjeldahl Method
- Dr. Jim's BIG WHOOSH!!
127
In the presence of cupric ions, this test yields a violet color; intensity of color produced is proportional to the number of peptide bonds present to bind w/ cupric ions in alkaline solution
Biuret Method
128
Based on the refractive index of light; ratio of light refraction in two differing media is related to protein concentration
Refractometry
129
Dye-binding method using bromocresol green or bromocresol purple
Albumin Method
130
Quantitative passie diffusion, Ag in serum diffuses from well until Ab excess causes immune precipitation, observed as ring around well
Radial immunodiffusion (RID)
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All antigenic sites are covered w/ Ab and lattic formation is inhibited; more Ab than Ag
Prozone, Ab excess
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Optimal proportion of Ab and Ag; 2-3 molecules are present for each Ag moleucle; maximum lattice formation and maximum precipitate; insoluble complexes
Equivalence zone
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Ag excess; all Ab sites are saturated by Ag; more Ag than Ab
Postzone
134
The migration of charged solutes or particles (proteins) in a liquid medium under the influence of an applied external electrical field
Electrophoresis
135
3 support media for electrophoresis
1. Agarose gel
2. Cellulose acetate
3. Polyacrylamide gel
136
Acidic pH = protein is a \_\_\_\_
Cation
137
The cation migrates to the \_\_\_\_, which is a ____ pole
Cathod; negative
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Alkaline pH = protein is an \_\_\_\_, and migrates to the anode, which is a ____ pole
Anion; positive
139
Migration pattern from anode to cathode for serum protein electrophoresis
Albumin, then alpha1 globulins, then alpha2 globulins, then beta globulins, then gamma globulins
140
The following electrophoresis data describes \_\_\_\_
↓ albumin and beta regions
↑ alpha1 and alpha2 regions
Overall ↓ total protein
Acute inflammation
141
The following electrophoresis data describes \_\_\_\_
↓ albumin
↑ alpha1, alpha2, beta, gamma globulins
Overall ↑ total protein
Chronic inflammation
142
The following electrophresis data describes \_\_\_\_
↑ alpha2 and beta globulins
only 4 peaks causing a beta-gamma bridge followed by an M-spike
Cirrhosis
143
The following electrophoresis data describes \_\_\_\_
↓ albumin, alpha1, beta, gamma globulins
↑ alpha2 globulins
Overall ↓ total protein
Nephrotic syndrome
144
The following electrophoresis data describes \_\_\_\_
↓ gamma globulins
Hypogammaglobulinemia
145
The following electrophoresis data describes \_\_\_\_
↑ gamma globulins causing an M-spike
Overall ↑ total protein
Hypergammagloulinemia (monoclonal gammopathy)
146
The following electrophoresis data describes \_\_\_\_
↑ gamma region
Polyclonal gammopathy (diffuse increase in gamma region)
147
The following electrophoresis data describes \_\_\_\_
↓ alpha1 region
Alpha1 antitrypsin deficiency
148
2 causes of increased CSF total protein
1. Increased endogenous production (i.e, MS)
2. Damage to BBB causing leakage of blood into CNS (infections, stroke, skull fracture, etc)
149
About 90% of patients w/ MS have a(n) ____ CSF IgG index ( \> 0.70)
- What is the calculation to find the CSF IgG index?
Increased
(IgGCSF x albuminserum) / (IgGserum x albuminCSF)
150
The synthesis of complex molecules in living organisms from simpler ones together w/ the storage of energy
Anabolism
151
The breakdown of complex molecules in living organisms to form simpler ones, together w/ the release of energy
Catabolism
