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69 Cards in this Set
- Front
- Back
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Macromolecules that consist of covalently linked polymers of amino acids
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proteins
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amino acids are linked to each other through
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peptide bonds
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-inherited enzyme defects that inhibit metabolism of certain amino acids
-exist either in activity of specific enzyme in metabolic pathway or in membrane transport system for amino acids -cause severe medical complications due to build-up of toxic amino acids& byproducts of amino acid metabolism in blood |
Aminoacidopathies
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-phenylketonuria
-tyrosinemia -alkaptonuria -MSUD -isovaleric acidemia -homocytinuria -citrullinemia -cystinuria |
Aminoacidopathies; phenylketonuria is most common
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In amino acid analysis what are the requirements
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-blood drawn after at least 6-8 hr fast
- heparin tube must be used -plasma removed - analysis performed immediately or stored at -20- -40 degrees C. |
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why is a heparin tube used?
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doesnt speed up or slow down reactions
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gold method for amino acid analysis
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thin layer chromatography
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determined by number and types of amino acids and their sequence in polypeptide chain
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primary structure of protein
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determined by winding of polypeptide chain-- alpha helix, beta pleated sheet, or random coil
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secondary structure of a protein
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determined by the way the twisted chain folds back on itself to form 3 dimensional structure
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tertiary structure of protein
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Components of proteins (5)
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-carbon
-hydrogen -oxygen -sulfer -Nitrogen |
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component of protein that differentiates proteins from everything else
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nitrogen (16%)
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another name for an ampholyte
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zwitterion
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amino acids containing 2 ionizable sites and at physiologic pH (7.4), both carboxyl and amino sites are ionized(have pos.and neg. charge on same molecule)
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ampholyte or zwitterion
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pH at which amino acid is nuetrol, having no net surface charge
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isoelectric point
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functions of proteins
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-carrier molecules
-maintenance of osmotic pressure -immune response agents -enzymes -acts as a marker for nutrition -acts as a marker for liver function |
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reference range for total protein
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6.5-8.3 g/dL
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protein samples include
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serum, plasma, CSF, and urine
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four methods for protein analysis
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Kjeldahl, Biuret, dye binding, refractometry
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-digestion of protein, measures nitrogen content
-gold standard -reference method; assumes nitrogen content of 16% |
Kjeldahl
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-formation of violet colored chelate between Cu2+ ions and peptide bonds
-routine method;requires at least two peptide bonds and an alkaline medium (pH=7) -measures the number of peptide bonds connected to Cu2+ molecules |
Biuret method
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-protein binds to dye and causes a spectral shift in the absorbance maximum of the dye
-research use |
dye binding method
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gold standard for hgb used in chromatography
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HPLC
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two methods in seperating serum proteins
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chromatography, electrophoreisis
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method of choice in seperating serum proteins
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electrophoreisis
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medium of choice in electrophoreisis
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polyacrylamide gel
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medium used in electrophoreisis in Hgb
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cellulose acetate
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Two main groups of protein fractions
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albumin and globulins
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Albumin fractions include? and their charge?
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pre-albumin and albumin; negative, they travel towards the cathode
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Globulin fractions include? and their charges?
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a-1 proteins, a-2 proteins, beta proteins(b-1,b-2), gamma; positive, they travel towards the anodes
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-thyroxine-binding protein, also called transthyretin or TPBA
-transports T3 and T4 -Molecular weight is 54,000 -synthesized by liver |
pre-albumin
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-sensitive marker of poor nutritional status
-half life of only two days -decreased in hepatic damage, burns, salicylate ingestion, and tissure necrosis |
pre-albumin
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-molecular weight 66,000
-present in highest concentration in serum -synthesized in liver |
albumin
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functions include:
-maintaining fluid balance -transport molecule for less soluble substances -anti oxidant activity -buffers pH |
Albumin
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Preferred method for albumin testing is...
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dye binding
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-Albumin binds to dye causes shift in absorption maximum
-most commonly used -sensitive;overestimates low albumin levels |
BCG
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-increased albumin
-dehydration -rare and of no clinical significance |
hyperalbuminemia
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-decreased albumin
-cuased by either impaired synthesis or protein loss -of clinical significance cause may point to liver or kidney issue |
hypoalbuminemia
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-absence of albumin
-rare genetic abnormality - aymptomatic except for slight edema |
Analabuminemia
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-congenital conditions characterized by the prescence of albumin that has unusual molecular characteristics-- two identical bands on electrophoreisis
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bisalbuminemia
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-has highest concentration w/in its globulin fraction
-group of serine protesase inhibitors synthesized in the liver -protease inhibitor that binds to and inactivates trypsin like enzymes that that cause hydrolytic gamage to structural proteins |
a-1 Antitrypsin
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-deficiency is inherited in homozygous or heterozygous state is linked to pulmonary emphysema and cirrhosis
- increased levels in inflammatory reactions, pregnancy, and oral contraceptive use |
a-1 antityrypsin
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-synthesized by the fetal liver
-major fetal protein during 2nd trimester Increased AFP in meternal serum indicates twins or high risk for open nueral tube defects (ONTD) |
a-1 fetoprotein (AFP)
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-decreased levels indicate increased risk for down syndrome
-also used as a tumor marker and is elevated in cancers of liver |
a-1 fetoprotein (AFP)
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-synthesized by liver
-biological function unknown -inactivates progesterone and binds basic drugs |
a-1 acid glycoprotein
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-largest non immunoglobulin in serum
-inhibits proteases such as trypsin, pepsin, and plasmin and binds to some horomones such as insulin and is removed by the RES -increased in nephrotic syndrome |
a-2 Macroglobulin
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-binds free hemoglobin and transports it to the RE system where hemoglobin is degraded
-prevents loss of hgb and its and its iron into the urine |
Haptoglobin
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-decreased in hemolytic diseases- HDN and transfusion reactions
-increased in inflammatory conditions, burns and nephrotic syndrome |
haptoglobin
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-copper containing a2 glycoprotein, synthesized in liver
-decreased levels found in Wilson's disease and Menke's disease |
ceruloplasmin
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-proteins that increase in response to inflammation
-frequently occur as a result of an MI, tumor growth, surgery or trauma -play a role in host defense |
acute phase reactant (APR)
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Name acute phase reactants (6)
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CRP
AAT C3 AAG haptoglobin ceruloplasmin |
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what happens to total protein levels during inflammation when APRs increase
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changes very little or stays same
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-most predominant of beta fractions
-synthesized in liver -binds and transports iron and prevents its loss through the kidneys |
Transferrin
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-increased in iron deficiency anemia, pregnancy, and estrogen therapy
-decreased in infection, inflammation, kidney disease, malignancy and hereditary atranserrinemia |
Transferrin
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When transferrin deposits are low, what happens to iron
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iron deposits form in other tissues
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-found on the surface of most nucleated cells, particularly lymphocytes
-small protein -urinary sample of this is used to measure renal tubular function -elevated in renal failure, inflammation, and malignancies, rhuematoid arthritis, HIV |
B-2 Microglobulin (B2M)
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-synthesized in liver
-peak seen between beta and gamma fractions -increased in pregnancy and with use of birth control pills -decreased in extensive coagulation and is an APR |
Fibrinogen
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-Proteins that participate in the immune reaction and serve as a link to the inflammatory response.
-increased in inflammatory condition -decreased in malnutrition, lupus, and intravascular coagulopathies. |
Complement
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-Most clinically important APR
- First APR to rise in response to inflammatory disease, significantly high in acute rhuematic fever, bacterial infections, MI and viral infections -Recognized as an independent risk factor in cardiovascular disease |
C- reactive protein
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-includes immunoglobulins
-synthesized by plasma cells from the B lymohocyte lineage in bone marro -immunoglobulins are composed of 2 identical heavy and 2 identical light |
gamma globulins
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a single sharp peak in gamma redion indicates? and is indicateve of what?
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monoclonal gammopathy from one cell line; multiple myeloma
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a broad peak, homogenous gamma fraction or multiple bands indicate
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polyclonal gammamopathy (indicates inflammation)
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increased in liver disease, autoimmune diseases and infections (immunoglobulin)
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IgG
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First to appear in response to antigen stimulation. Monoclonal increase is seen in Waldenstrom's macroglobulinemia
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IgM
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-a secretory antibody found in saliva, tears, sweat and nasal secretions
-Beta-gamma bridging is seen in chirrosis |
IgA
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-associated with allergic and anaphylactic reactions
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IgE
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caused by excessive loss due to renal disease, leakage into GI tract and bleeding. decreased intake due to malnutrition and malabsorption
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hypoproteinemia
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caused by dehydration due to vomiting and diarrhea and excessive protein production such as Bence jones protein in multiple myeloma
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Hyperporoteinemia
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Protein in multiple myeloma responsible for monoclonal gammopathy
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Bence Jones protein
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