Plasma Proteins Flashcards
Name the major types of plasma proteins in blood
60% albumin
18-30% globulins
4% fibrinogen
<1% regulatory proteins
What is the major role of albumin?
major contributor to osmotic pressure of plasma
assists in the transport of lipids, steroid hormones, and drugs
What is the major purpose of globulins?
includes immunoglobulins - also proteins used in the transport of ions, hormones and lipids
what is the function of fibrinogen?
mainly clotting function
deficiency in the production of circulating alpha1 antiTrypsin is related to what disease?
Emphysema
All of the plasma proteins (except complement and immunoglobulins) are synthesized where?
They are synthesized in the liver -
complement proteins are synthesized in macrophages as well
immunoglobulins are synthesized in activated B lymphocytes
All plasma proteins except albumin are …?
glycoproteins - have carbohydrate attached to them (sialic acid)
Where does loss of plasma proteins occur?
in the kidneys and GIT
What is electrophoresis used for?
It is used to separate proteins according to their electrical charge/molecular size
What are the five major groups of plasma proteins separated by eletrophoresis?
albumin, alpha1, alpha2, beta, and gamma globulins
*densitometry allows relative quantification of protein bands - albumin should obviously make the biggest peak b/c it is most prevalent in plasma*
Where does albumin migrate on an electrophoresis?
It migrates to the anode- I assume b/c it has a positive charge?
What does the alpha 1 globulin peak on electrophoresis contain?
- alpha 1 protease inhibitor
- alpha 1 glycoprotein
- alpha fetoprotein
- high density lipoprotein
What does the alpha 2 globulin peak contain?
- alpha 2 macroglobulin
- antithrombin 3
- ceruloplasmin
- hapatoglobin - most predominant component
What does the beta globulin peak on electrophoresis contain?
- beta and prebeta lipoproteins
- compliment proteins
- CRP
- hemoglobin (free)
- plasminogen
- Transferrin
What does the gamma globulin peak on electrophoresis contain?
they are synthesized by B lymphocytes and plasma cells of immune system
- Ig
- IgA
- IgD
- IgE
- IgG+
- IgM
What human plasma proteins exhibit polymorphism?(polymorphism is a mendelian or monogenic trait that exists in the population in at least two phenotypes like the ABO blood types)
- alpha 1 antitrypsin
- hepatoglobin
- transferring
- ceruloplasmin
- immunoglobulins
What are acute phase proteins?
they are a class of proteins whose plasma concentrations increase or decrease in response to trauma
- local inflammatory cells (neutrophil, granulocytes, and macrophages) secrete a number of cytokins into the bloodstream
- the liver responds by producing a large number of acute phase reactants
What can Acute phase responses be induced by?
malignancy
autoimmune disease
trauma (surgery, accidents etc)
infections
In an acute phase reponse, we see an increase in what plasma proteins?
- C reactive proteins
- Alpha 1 acid glycoprotin
- alpha 1 anti trypsin
- antithrombin 3
- C3
- ceruloplamin
- fibrinogen
- hepatoglobin
what plasma proteins are reduced in response to an acute phase response?
- levels of albumin and transferrin are reduced
What are the functions of albumin?
- maintains colloidal osmotic pressure
- nutrition - source of amino acids for tissue protein synthesis
- transport protein - binds to lipid soluble hormones and free fatty acids
- buffering function - high histadine residue content
Why might hypo-albuminemia cause muscle weakness?
albumin binds and transfers calcium to the muscle cells - therefore, hypoalbuminemia can cause muscle weakness
does increased serum albumin occure naturally?
no - your liver doesn’t produce ‘too much ‘ albumin ever
what are some causes of decreased serum albumin?
- protein malnutrition - alcoholism, celiac disease, pancreatic duct problems, crohn’s, whipple’s, cystic fibrosis etc.
- hepatocellular disease - decreased synthesis
- nephrotic syndrome - increased loss through kidney
- thermal burns - loss through skin
- acute or chronic inflammation
What is the function of alpha 1 anti trypsin?
it is the principle protease inhibitor in the plasma
It is also a potent inhibitor of elastase- a proteolytic enzyme secreted by inflammatory cells
What is the function of haptoglobin (alpha 2 globulin)?
it is an immunoglobulin-like plasma protein that binds free plasma hemoglobin -
What is the function of C-Reactive Protein?
it was originally discovered as a substance in the serum of patinets with acute inflammation that reacted with Capsular polysaccharide of pneumococcus bacteria - its role is to bind to phosphocholine expressed on the surface of dead or dyig cells in order to activate the Complement systme
What is the function of immunoglobulins?
they are secreted in response to ‘non-self’ proteins being recognized - they bind to and eliminate the immunogen - ex) IgG, IgA, IgM etc
Where are IgA antibodies found?
mucosal areas like the gut, respiratory tract, urogenital tract etc. - prevents colonization of pathogens
what is the function of IgD?
mainly functions as an antigen receptor on B cells- it’s function is less defined than other types
What is the function of IgE?
binds to allergens and triggers histamine release from mast cells, and is invovled in allergies
What is the function of IgG?
provides the majority of antibody based immunity against invading pathogens
What is the purpose of IgM?
it is expressed on the surface of B cells and in a secreted form with very high acidity. It eliminates pathogens in the early stages of B cell mediated immunity before there is sufficient IgG
What enzyme cleaves fribrinogen?
Thombin
What is associated with high or low levels of Fibrinogen?
increased levels = associated with inflammation (it is an acute phase protein) cardiovascular disease, and levels also increase in pregnancy
decreased= low levels can indicate a systemic activation of the clotting system - with the consumption of clotting factors faster than the synthesis
