Plasma proteins Flashcards
What is the most important plasma protein?
Albumin
What are the functions of plasma proteins?
Transport Humoral immunity Maintenance of oncotic pressure Protease inhibitors Buffering Enzymes/Hormones
Give examples of proteins associated with transport
Transferrin, apolipoproteins,
Give an example of proteins associated with humoral immunity
Immunoglobins
Give an example of proteins associated with buffering
all plasma proteins
Give an example of protease inhibitors
alpha 1 anti-trypsin
Give an example of proteins associated with enzymes and hormones
Renin, coagulation factors, complement proteins
What could cause a decrease in protein concentration?
Malnutrition Malabsorption Liver disease Over hydration increased capillary permeability catabolic state
What could cause an increase in protein concentration?
Dehydration
paraproteinemia
hypergammaglobulinemia
How is plasma protein measured in electrophoresis?
The proteins are separated based on electrical charge
5 separate bands are seen
These bands can vary depending on the disease
Which proteins are observed in each of the 5 bands in order?
Albumin first alpha-1 proteins alpha-2 proteins beta-1 proteins beta-2 proteins gamma globulins
Give examples of alpha 1 and alpha 2 proteins
alpha-1: AT, a-fetoprotein
alpha-2: HDL, Haptoglobin, a2-macroglobulin, ceruloplasmin
Give examples of beta 1 and 2 proteins
C3, transferrin, LDL, CRP,
Give examples of gamma globulins.
Immunoglobulins, fibrinogen,
What is Prealbumin (Transthyretin)?
It is a transport protein for thyroid hormones and retinol(vit A)
It migrates faster than albumin in electrophoresis and low levels are common in liver disease, nephrotic syndrome and acute phase inflammatory response as well as malnutrition. It only has a half life of 2 days
What is albumin?
Albumin is the most abundant protein found in the body and is synthesized in the liver. It has a 20 day half life and can decrease rapidly following an injury or surgery. Its main function is the maintenance of oncotic pressure(80%)
What is oncotic pressure?
This is the osmotic pressure that plasma proteins exert to pull water into the circulatory system. It is the opposing force to hydrostatic pressure and it maintains fluid distribution in and outside cells
What are the effects of Hypoalbumineamia?
The low oncotic pressure leads to oedema as albumin levels drop such as in liver disease, this causes fluid to move into the interstitial spaces.
There is reduced transport of drugs and other substances in plasma.
There is reduced amount of protein bound calcium and total plasma calcium level drops but ionized calcium may remain normal
What is the main cause of hyperalbuminemia?
Dehydration
No clinical conditions associated with liver producing large amounts of albumin.
What is alpha-1 antitrypsin?
It is a protein made by the liver and macrophages which naturally inhibits proteases.
It is an acute phase protein, and increase in acute inflammation
What inherited disorders disrupt synthesis of alpha-1 AT?
Emphysema
cirrhosis
neonatal hepatitis
What is Haptoglobin?
An acute phase protein and alpha-2 globulin whos main function is to bind to free haemoglobin and transfer it to reticuloendothelial cells.
Its concentration can increase in hypoalbuminemic states and genetic ploymorphism is present
What is alpha-2 macroglobulin?
A protein with a high molecular weight that acts as a protease inhibitor. It is increased in nephrotic syndrome and accounts for 1/3 of alpha 2 globulins
What is ceruloplasmin?
An acute phase protein that carries copper and is a ferroxidase and superoxide scavenger. Its significant in the absorption of oxygen in the intestine and Can cause wilsons disease when in low ammounts.
What is Wilsons disease?
A disease where copper accumulates in the liver and brain due to low levels of ceruloplasmin
What is transferrin?
A beta globulin majorly associated with transporting iron. It binds to free iron in serum
What is C-reactive protein?(CRP)
An acute phase protein synthesized by the liver that is important for phagocytosis. High levels of it are found in inflammatory conditions such as rheumatoid arthritis and it can ACT AS A MARKER FOR ISCHEMIC HEART DISEASE
What is Pro-calcitonin?
A precursor to calcitonin
It undergoes cleavage in C cells of the thyroid gland to form calcitonin and it is an acute phase protein.
It has a greater sensitivity and specificity to infection than CRP and is a better prognostic indicator
What is an acute phase response?
A complex physiological change that occurs in trauma, burns, infection and inflammation that is mediated by cytokines, TNF and vasoactive substances.
It can cause changes in plasma proteins and hemodynamics as well as increase fibrinolytic and coagulation systems. Can also cause systemic effects
what are some positive acute phase proteins(increase in response)
a1-AT Haptoglobin ceruloplasmin CRP fibrinogen
What are some negative acute phase proteins (decrease in response)
Albumin
prealbumin
transferrin
What is the function of positive acute phase proteins and which mediators lead to their increase?
They activate the complement system
Bind to bacterial cell walls and stimulate phagocytosis
Mediators include: Cytokines, TNF alpha and beta, interferons and platelet activating factors
What are immunoglobulins?
Plasma proteins that act as antibodies and recognize and bind to foreign antigens
What happens if protein concentration falls?
capillary permeability will increase leading to diffusion of protein out of interstitial space. This leads to
Septicemia & Inflammation
