Amino Acids and Proteins Flashcards
Class of inherited errors of metabolism in which there is an enzyme defect that inhibits the body’s ability to metabolize certain amino acids
Aminoacidopathies
Cause of phenylketonuria
Phenylalanine hydroxylase (PAH)
deficiency
Urine odor of patient with phenylketonuria
Musty/Mousy odor
Patients with PKU may experience
Mental retardation
Microcephaly
A co-factor in the enzymatic hydroxylation of phenylalanine, tryptophan, and tyrosine
Tetrahydrobiopterin
Non-protein chemical/entity that must bind to a particular enzyme before a reaction occurs
Co-factor
Allows early detection IEM and early implementation of the treatment
Newborn screening test
Goal of PKU treatment
Maintain blood level of phenylalanine (2-10 mg/dL or 120- 160 μmol/L)
First drug to manage PKU
Kuvan (sapropterin dihydrochloride)
Positive result of Ferric Chloride Tube Test for PKU
Permanent blue-green color
Positive result of Guthrie Bacterial Inhibition Test for PKU
Bacterial growth
Inhibitor of B. subtilis
B-2-thienylalanine
Reference method for quantitative serum phenylalanine
High-Performance Liquid Chromatography (HPLC)
Used in screening for inherited disorders in newborns
Tandem Mass Spectrometry (MS/MS)
Characterized by the excretion of tyrosine and tyrosine catabolites in urine
Tyrosinemia
Cause of type 1 tyrosinemia
Fumarylacetoacetate hydrolase deficiency
Most severe form of tyrosinemia
Type 1
Cause of type 2 tyrosinemia
Tyrosine aminotransferase deficiency
Cause of type 3 tyrosinemia
4-hydroxyphenylpyruvate dioxygenase or p-hydroxyphenylpyruvic acid dioxygenase deficiency
Positive result of Ferric chloride tube test for tyrosinemia
Transient green color
Positive result of Nitroso-naphthol test for tyrosinemia
Orange-red color
Drug to treat tyrosinemia
Nitrisinone
Cause of alkaptonuria
Homogentisate oxidase deficiency
Urine color of patient with alkaptonuria
Brownish-black after exposure to air
Positive result of Ferric chloride tube test for alkaptonuria
Deep blue/black
Positive result of Clinitest for alkaptonuria
Yellow precipitate
Positive result of Homogentisic acid test for alkaptonuria
Black
Treatment for alkaptonuria
Vitamin C
Cause of MSUD
α-ketoacid decarboxylase deficiency or defect
MSUD blocks the normal metabolism of the three essential branched-chain amino acids: _____, _____, _____
Leucine
Isoleucine
Valine
Urine odor of patient with MSUD
Maple syrup or burnt sugar odor
Positive result of 2,4-dinitrophenylhydrazine (DNPH) test for MSUD
Yellow precipitate or turbidity
Cause of isovaleric acidemia
Isovaleryl-CoA dehydrogenase deficiency
Urine odor of patients with isovaleric acidemia
Sweaty feet odor, due to build-up of isovaleric acid
Positive result of p-Nitroaniline Test for isovaleric acidemia
Emerald green
Cause of homocystinuria
Cystathionine β-synthase deficiency
Positive result of Cyanide-nitroprusside test for homocystinuria
Red-purple color
Positive result of Silver-nitroprusside test for homocystinuria
Red-purple color
Class of genetic diseases called urea cycle disorders
Citrullinemmia
Types of citrullinemia
TYPE 1: the most common form, lack of the enzyme argininosuccinic acid synthetase (buildup of citrulline and ammonia in the blood)
TYPE 2: caused by a mutation of the gene that makes the protein citrin
Cause of arginosuccinic aciduria
Argininosuccinic acid lyase deficiency
Positive result of Cyanide-Nitroprusside Test for Cystine
Red-purple
Blood samples for amino acid analysis should be drawn after
At least a 6-8 hour fast
Tube and additive used in samples for amino acid analysis
Heparin; green tube
Deproteinization should be performed within _____ of sample collection and analysis should be performed _____
30 minutes
Immediately
In cases that a sample cannot be analyzed immediately, the sample should be
Frozen at −20°C to −40°C
Urinary amino acid analysis can be performed on random specimens. True or False?
True
Urine preservative for protein analyses
Thymol
Method of choice for screening test of amino acids
Thin-layer chromatography
A process that allows the separation of ion and molecules base on affinity to ion exchangers
Ion exchange chromatography/ Ion chromatography
Possess negatively charged group and attract positively charged ion
Cationic exchangers
Possess positively charged group and attract negatively charged ion
Anionic exchangers
Separates ions base on electrophoretic mobility
with the use of applied voltage
Capillary electrophoresis
Technique use to break down selected ions/precursor ions into fragments or product ions (fragments reveal the aspect of the ion)
MS/MS (tandem mass spectrophotometry)
Are polymers of amino acids that are linked covalently through peptide bonds
Proteins
Protein are micromolecules. True or False?
False; macromolecules
All proteins are synthesized in the liver. True or False?
False; except immunoglobulins (plasma cells)
Atoms in protein compound
Carbon
Oxygen
Hydrogen
Nitrogen
Sulfur
4 structures of protein
Primary
Secondary
Tertiary
Quaternary
Linear sequence of amino acids
Primary structure
Protein structure that determines the identity of protein
Primary structure
Specific regular three-dimensional conformations into which portions of the polypeptide chain fold (α-helix; β-pleated sheets; bend conformation)
Secondary structure
Protein structure which adds new property such as strength and flexibility due to polypeptide chain fold
Secondary structure
Actual three-dimensional structure or folding pattern of the protein
Tertiary structure
Refers to overall shape and formation of protein
Tertiary structure
Protein structure with spatial relationship to one another
Tertiary structure
The shape or structure that results from the interaction of more than one protein molecule, or protein subunits
Quaternary structure
Most abundant protein in the body
Collagen
Process where protein loose its shape and functions
Denaturation
Causes of protein denaturation
Heat
Hydrolysis
Strong acids
Alkali
Enzymatic reaction
Exposure to urea
UV light
Classification of proteins by function
Enzymes
Hormones
Transport proteins
Immunoglobulins
Structural proteins
Storage proteins
Energy source
Osmotic source
Catalyze chemical reactions
Enzymes
Chemical messengers that control action of specific organ or system
Hormones
Transport movement of ions, small molecules, or macromolecules
Transport proteins
Mediate the humoral immune response
Immunoglobulins
The only protein not produced by the liver
Immunoglobulins
Proteins for structures of cells and tissues
Structural proteins
Protein that serve as reserves of metal ions and amino acids
Storage proteins
Protein for tissues and muscles
Energy source proteins
Function in the distribution of water throughout the compartments of the body
Osmotic force proteins
Example of osmotic force proteins
Albumin (important in colloid osmotic pressure)
Structural Classification of Proteins (SCOP) database
Class
Fold
Superfamily
Family
Families of Structurally Similar Proteins (FSSP) / Fold Classification is based on
Three-dimensional structure of proteins
Protein that contains peptide chains of only amino acids
Simple Proteins
Examples of globular proteins
Albumin
Hemoglobin
Examples of fibrous proteins
Troponin
Collagen
Consist of a protein and a non-protein (prosthetic) group
Conjugated Proteins
Metals + Proteins
Metalloproteins
Examples of metalloproteins
Ferritin
Ceruloplasmin
Lipids + Proteins
Lipoproteins
Examples of lipoproteins
High Density Lipoprotein
Low Density Lipoprotein
Very Low-Density Lipoprotein
Chylomicrons
Carbohydrates + Protein (10-40% Carbs)
Glycoproteins
Examples of glycoproteins
Haptoglobin
Alpha-1 antitrypsin
Carbohydrates + Proteins (>40% of Carbs)
Mucoproteins
Chromatin – DNA + Histones
Nucleoproteins
The most frequently analyzed of all the proteins
Plasma proteins
Two groups of plasma proteins
Albumin
Globulin
Alpha-1
Alpha-2
Beta
Gamma
Migrates before albumin in a classic electrophoresis
Prealbumin (Transthyretin)
The transport protein for thyroxine (T4) and triiodothyronine (T3) (thyroid hormones)
Prealbumin
Binds with retinol-binding protein (Vitamin A)
Prealbumin
Causes of decreased prealbumin
Hepatic Damage
Acute-phase inflammatory response
Tissue necrosis
Causes of increased prealbumin
Alcoholism
Steroid medication
Chronic Renal failure
Sensitive marker of nutritional status
Prealbumin
In terms of nutritional status, a decrease in prealbumin indicates
Poor nutrition
Most abundant protein in plasma
Albumin
Responsible for nearly 80% of the colloid osmotic pressure (COP) of the intravascular fluid
Albumin
Osmotic pressure exerted by large molecules like albumin which helps fluid stay within the instead of leaking into tissues
Colloid Osmotic Pressure
Concentration of this protein decreases during inflammation
Negative acute-phase reactant protein
Causes of decreased albumin
Malnutrition and malabsorption
Liver disease
Protein-losing enteropathy or gastrointestinal loss
Renal disease
Burns or exfoliative dermatitis
Hypothyroidism
Polydipsia or excess administration of IV fluid
Mutation causing analbuminemia or bisalbuminemia
Sepsis
Causes of increased albumin
Dehydration
After excessive albumin infusion
Albumin with unusual molecular
characteristics
Bisalbuminemia
Increased vascular permeability in the capillary
Sepsis
Cause of α1-antitrypsin deficiency
Mutations in the SERPINA1 gene [Serine Protease Inhibitor (SERPIN) Family A Member 1]
Provides information for a-1
Antitrypsin synthesis
SERPINA1
Concentration increases during inflammation
Acute-phase reactant
Causes of increased a1-antitrypsin
Inflammatory reactions
Pregnancy
Contraceptive use
Sites for A1-Antitrypsin synthesis
Human Amniotic epithelial cells
Liver
Major component of a1-globulin fraction
a1-antitrypsin
Binds the hormone estradiol (normal fetuses)
a1-Fetoprotein (AFP)
a1-Fetoprotein (AFP) is produced by
Developing embryo and fetus
Parenchymal cells of the liver
a1-Fetoprotein (AFP) increases after birth. True or False?
False; decreases
Protects the fetus from immunologic attack by the mother
a1-Fetoprotein (AFP)
Causes of increased a1-Fetoprotein (AFP)
Neural tube defects (spina bifida and anencephaly)
Abdominal wall defects
Fetal distress
Causes of decreased a1-Fetoprotein (AFP)
Down syndrome (Trisomy 21)
Edward’s Syndrome (Trisomy 18)
a1-Acid Glycoprotein (Orosomucoid) is a negative acute-phase reactant. True or False?
False; acute-phase reactant
Causes of increased a1-Acid Glycoprotein (Orosomucoid)
Stress
Inflammation
Tissue damage
Acute myocardial infarction (AMI)
Trauma
Pregnancy
Cancer
Pneumonia
Rheumatoid arthritis
Surgery
Serine proteinase inhibitor
α1-Antichymotrypsin
Cause of increased α1-Antichymotrypsin
Inflammation
Cause of decreased α1-Antichymotrypsin
Liver disease
Mutations in α1-Antichymotrypsin production may lead to
Parkinson’s disease
COPD
Alzheimer’s disease (amyloid deposits)
Play a role in inflammation and carcinogenesis
Inter-α-Trypsin Inhibitors
Cause of increased Inter-α-Trypsin Inhibitors
Inflammatory disorders
Major carrier protein of vitamin D and its metabolites in the VV (In VIVO)
Gc-Globulin (Group-Specific Component; Vitamin D–Binding Protein)
Causes of decreased Gc-Globulin
Severe liver disease
Protein-losing syndromes
Bind free hemoglobin to prevent the loss of hemoglobin and its constituent, iron
Haptoglobin
Used to evaluate degree of intravascular hemolysis (HTR and HDN)
Haptoglobin
Causes of increased Haptoglobin
Inflammatory diseases
Burns
Nephrotic syndrome
Cause of decreased Haptoglobin
Hemolytic anemia
Symptoms of Nephrotic syndrome
Massive proteinuria
Hypoalbuminemia
Hyperlipidemia
Occurs due to the mismatch or incompatibility of a patient with the donor products
Hemolytic Transfusion Reaction (HTR)
Occurs when the mother is Rh negative and has a baby who is Rh positive
Hemolytic Disease of the Newborn (HDN)
Given to mothers who is Rh negative around 28 weeks of pregnancy
RhoGAM / Rh immunoglobulin
Copper-containing α2-glycoprotein
Ceruloplasmin
90% of copper is bound to _____; 10% is bound to _____
Ceruloplasmin
Albumin
Causes of increased Ceruloplasmin
Inflammation
Cancers
Pregnancy
Causes of decreased Ceruloplasmin
Wilson’s disease
Malnutrition
Malabsorption
Severe liver disease
Nephrotic syndrome
Menkes syndrome (kinky hair disease)
Used to diagnose Wilson’s disease
Kayser-Fleischer rings in cornea
Autosomal recessive inherited disorder associated with decrease levels of the protein ceruloplasmin and a subsequent increase in copper causing it to accumulate in liver, brain and other organs
Wilson’s disease
Major component of the α2 band
a2-Macroglobulin
Functions of a2-Macroglobulin
Inhibits proteases such as trypsin, thrombin, kallikrein, and plasmin
Proteolytic enzyme that functions in the digestion of protein
Trypsin
Enzymes that play a role in the coagulation system
Thrombin
Kallikrein
Plasmin
Causes of increased a2-Macroglobulin
Nephrosis
Diabetes and liver disease
Indicates the amount of iron in the body
Transferrin (Siderophilin)
Causes of increased Transferrin (Siderophilin)
Liver disease
Malnutrition
Nephrotic syndrome
Causes of decreased Transferrin (Siderophilin)
Iron Deficiency Anemia (IDA)
Hemochromatosis (bronze skin) or Bronze Diabetes
Most prevalent nutritional deficit in the world
Iron Deficiency Anemia (IDA)
Major component of the β-globulin fraction
Transferrin (Siderophilin)
Function of Transferrin (Siderophilin)
Transport of iron and the prevention of loss of iron through the kidney
Organ that synthesize transferrin
Liver
Indication of high levels of transferrin
Signifies low iron which means there is less iron bound to transferrin
Iron Deficiency
Binds heme released by hemoglobin degradation and the complex is carried to the liver where it is destroyed
Hemopexin
Causes of increased Hemopexin
Inflammation
Diabetes mellitus
Duchenne type muscular dystrophy
Some malignancies
Causes of decreased Hemopexin
Hemolytic anemia or intravascular hemolytic anemia
Progressive muscle degeneration in weakness due to the alteration in the protein dystrophin that helps keep muscle intact
Duchenne type muscular dystrophy
Protein that is essential in muscular contractions
Dystrophin
Serum hemopexin level reflects how much heme is present in the blood, therefore, a low hemopexin level indicates decreased degradation of heme containing compounds. True or False?
False; significant degradation of heme containing compounds
Transport cholesterol, triglycerides, and phospholipids in the blood
Lipoproteins
The light chain component of the major histocompatibility complex
β2-Microglobulin
Function of Major Histocompatibility Complex (MHC)
Bind peptide fragments derived from pathogens and display them on the cell surface ready for recognition by appropriate T-lymphocytes
Causes of increased β2-Microglobulin
Rheumatoid arthritis
Systemic lupus erythematosus
HIV
Group of proteins that help your immune system to fight infection, heal injury and kill bacteria and viruses
Complement system
The most abundant complement in serum
C3
Cause of increased complement
Inflammatory conditions
Causes of decreased complement
Malnutrition
Hemolytic anemia
CD affected in Paroxysmal Nocturnal
Hemoglobinuria (PNH)
CD59
CD55
Form a fibrin clot when activated by thrombin
Fibrinogen
One of the largest proteins in blood plasma
Fibrinogen
Causes of increased fibrinogen
Inflammatory disorders
Pregnancy
Oral contraceptives
Cause of decreased fibrinogen
Extensive coagulation
One of the first acute-phase reactant proteins to rise in response to inflammatory disorders
C-Reactive Protein (CRP)
Causes of increased C-Reactive Protein (CRP)
Acute rheumatic fever
Bacterial infections
Myocardial infarctions
Rheumatoid arthritis
Carcinomatosis
Gout
Viral infections
Glycoproteins composed of 82% to 96% protein and 4% to 18% carbohydrate produced by white blood cells, known as B cells, that confer humoral immunity
Immunoglobulins (Antibodies or Igs)
Humoral immunity is otherwise known as
Antibody-mediated immunity
5 classes of Immunoglobulins
IgG
IgA
IgM
IgD
IgE
The most abundant class of antibodies found in blood plasma and lymph
IgG
The main immunoglobulin found in mucous secretions (including tears, saliva, colostrum, vaginal fluid, etc.)
IgA
The first antibody that appears in response to antigenic stimulation
IgM
Antibody molecules that are present on the surface of most B cells
IgD
Antibody associated with allergic and anaphylactic reactions
IgE
The primary oxygen-carrying protein in striated and cardiac muscle
Myoglobin
Myoglobin is a cardiac biomarker. True or False?
True
Causes of increased myoglobin
AMI
Progressive muscular dystrophy
Crushing injury
Renal failure
Myoglobin is cardiac specific. True or False?
False; not cardiac specific
Cardiac troponins include
Troponin I (cTnI)
Troponin T (cTnT)
The “gold standard” in the diagnosis of acute coronary syndrome
Cardiac troponin
Blood supplied to the heart is suddenly blocked like in heart attack or myocardial infarction
Acute coronary syndrome (ACS)
Specific for myocardial damage
Cardiac Troponin
These are neurohormones that affect body fluid homeostasis and blood pressure
Brain natriuretic peptide or N-terminal brain natriuretic peptide
Neurohormones are anti hypertensive agents which functions to decrease blood pressure. True or False?
True
How does neurohormones affect fluid homeostasis?
Natriuresis
Diuresis
Refers to increased urinary sodium excretion
Natriuresis
Refers to increased urine excretion
Diuresis
Function of neurohormone in the maintenance of blood pressure
Decreasing angiotensin II
Inhibiting production of norepinephrine
Popular markers for congestive heart failure
Cardiac troponin
Glycoprotein used to help predict the short-term risk of premature delivery
Fetal fibronectin (fFN)
Amino acid fat hormone produced by adipocytes
Adiponectin
Causes of decreased adiponectin
Heart disease
Type 2 diabetes
Metabolic syndrome
Obesity
Correlation between adiponectin and body mass index (BMI)
Inverse correlation
“Prostaglandin D synthase”
B-trace protein
Established as an accurate marker of CSF leakage
B-trace protein
Potential marker in detecting impaired renal function
B-trace protein
Are proteolytic fragments of collagen I formed during bone resorption
Cross-linked C-telopeptides
The process wherein osteoclasts breakdown the bone tissue
Resorption
Biochemical marker of bone resorption
Cross-linked C-telopeptides
Cross-linked C-telopeptides are detected in
Serum and urine
A cysteine proteinase inhibitor
Cystatin C
New sensitive endogenous serum marker for the glomerular filtration rate
Cystatin C
Variety of conditions in which amyloid proteins are abnormally deposited in organs and/or tissues
Amyloidosis
Insoluble fibrous protein aggregates formed due to an alteration in their secondary structure, in particular the β-pleated sheet form
Amyloids
Help differentiate a diagnosis of Alzheimer disease from other forms of dementia
Amyloid β42 (Aβ42) and Tau protein tests
Indication of Low Aβ42 and high Tau
Reflects increased likelihood of Alzheimer disease
Transferrin-free protein that differentiates a CSF sample
Tau protein
Rough measure of all of the proteins in the plasma
Total protein
Decrease in blood protein concentration
Hypoproteinemia
Causes of hypoproteinemia
Excessive loss
Malnutrition
Malabsorption
Liver diseases
Increase in blood protein concentration
Hyperproteinemia
Causes of hyperproteinemia
Dehydration
Excessive production of globulins (γ-globulins)
Most abundant protein in plasma
Albumin
Albumin is a negative acute-phase reactant protein. True or False?
True
How to determine globulin fraction of albumin?
By subtracting the albumin from the total protein
Indication when there is a characteristic beta-gamma (β-y) bridging
Cirrhosis
Indication of increase in gamma (y)-globulins
Hepatitis
Indication of increased alpha-2-globulin and beta-globulin fractions
Obstructive jaundice
Measures all chemically bound nitrogen in the sample (either plasma or urine)
Total nitrogen
Emission of light created from a chemical or electrochemical reaction
Chemiluminescence
Principle of total nitrogen
Chemiluminescence
Most commonly used sample for total protein
Serum
Interferences of total protein
Lipemia
Hemolysis
Reference range for serum total protein in adults
6.5 to 8.3 g/dL (65 to 83 g/L)
Principle of Kjeldahl Method
Digestion of protein; measurement of nitrogen content
Reference method in the quantitation of total protein
Kjeldahl Method
Principle of Biuret Method
Formation of violet-colored chelate between Cu2+ ions and peptide bonds
In biuret method, that absorbance of chelate is measure at
540 nm
Routine method for total protein
Biuret Method
Principle of Dye binding
Protein binds to dye and causes a spectral shift in the absorbance maximum of the dye
Total Protein method used for research purposes
Dye binding
Dyes used in dye-binding method
Ponceau S
Bromophenol blue
Methyl orange
HABA [2,4’-hydroxyazobenzene-benzoic acid]
Bromocresol green
Bromocresol purple
Amido black 10B
Lissamine green
Coomassie Brilliant Blue)
Globulins are precipitated in high salt concentrations; albumin in supernatant is quantitated by biuret reaction
Salt precipitation
Proteins separated based on electric charge
Electrophoresis
Globulin is separated from albumin using sodium salts causing precipitation of globulin
Salt precipitation
Most widely used methods for albumin determination
Dye binding
Non-specific for albumin
Methyl orange
Used to quantitate albumin
Bromocresol green
Bromocresol purple
Support media used in albumin methods
Cellulose acetate
Agarose gel
In electrophoresis, cation (+) migrates to
Cathode (-)
In electrophoresis, anion (+) migrates to
Anode (+)
List the serum proteins
Albumin
α1- globulins
α2-globulins
β-globulins
γ-globulins
Serum protein that travels farthest to the anode
Albumin
Reference values for serum protein electrophoresis
Albumin, 53% to 65% of the total protein (3.5 to 5.0 g/dL)
α1-Globulin, 2.5% to 5% (0.1 to 0.3 g/dL)
α2-Globulin, 7% to 13% (0.6 to 1.0 g/dL)
β-Globulin, 8% to 14% (0.7 to 1.1 g/dL)
γ-Globulin, 12% to 22% (0.8 to 1.6 g/dL)
Decrease in the alpha 1 globulin
ALPHA 1 – ANTITRYPSIN DEFICIENCY
Increase in alpha 2 globulin because of the presence of alpha 2 macroglobulin and haptoglobin
Decrease in albumin
NEPHROTIC SYNDROME
Decrease in albumin.
Increase in alpha 1, alpha 2 and beta globulin
INFLAMMATION
Beta-gamma bridging is a unique characteristic that is seen in patients with
CIRRHOSIS
increase in immunoglobulin, result of monoclonal increase
MONOCLONAL INCREASE
A condition in which abnormal proteins are found in the blood
Monoclonal gammopathy
Separation of molecules in silica capillaries
CAPILLARY ELECTROPHORESIS
Zone electrophoresis that separates proteins on the basis of pI (Isoelectric Point)
ISOELECTRIC FOCUSING
Immunochemical Methods
Immunoturbidometry
Immunonephelometry
Presence of proteinuria is often associated with renal disease. True or False?
True
Principle of reagent strip test for protein
Protein error of indicator
Reagent used in reagent strip test for protein
Tetrabromophenol blue or tetrachlorophenol tetrabromosulphonphthalein
Quantitative test for urine protein
12 or 24-hour urine test
Precipitation tests for protein
Trichloroacetic acid (TCA)
Salicylic Acid (SSA)
Benzethonium Chloride
Presence of elevated levels of CSF protein is associated with damage to the blood-brain barrier. True or False?
True
Common causes of damaged BBB
Meningitis
Hemorrhage
Protein fraction used to evaluate the integrity of the blood brain barrier
CSF/Serum Albumin Index
Protein fraction used to measure immunoglobulin G synthesis within the CSF
CSF IgG Index
Elevated IgG in CSF is associated with
Multiple sclerosis
Method to detect oligoclonal bands which indicate inflammation within the CSF
Electrophoresis
