Plasma proteins Flashcards
what is the diff between serum and plasma
serum = liquid part of blood after coagulation
plasma = blood with anticoagulants in it to prevent clotting
where are plasma proteins produced
made in liver, except immunoglobulins
how many plasma proteins have been discovered
> 300
what are the functions of proteins
transport
maintaining oncotic pressure
buffer pH changes
defense (immunoglobulins)
coagulation + fibrinolysis
misc specialised functions
what are the three main fractions of plasma proteins
albumin: (60-70%)
globulins (38%)
fibrinogen (4%)
what are the diff globulins
a1-globulin (5.3%)
a2-globulin (8.6%)
B-globulin (13.4)
y-globulin (11%)
how can plasma proteins be measured
- quantitatively: measure a specific protein
- semi-quantitatively: electrophoretic measurement where the proteins are separated into bands which change in disease
- measurement of biological activity
- immunoassays
write a gen note on albumin
single polypeptide chain, 585aa length, most abundant in blood plasma (36-47g/L)
made in liver (12g per day) half life in plasma 2-3 weeks
transport functions of albumin
-bind and transport diverse molecules- have low specificity for transporting thinfs such as
-metal ions (calcium and copper)
- free fatty acids released by adipose tissues and facilitates transfer to other tissues
-bilirubin which protects from toxicity of unconjugated bilirubin
-bile acids that were recycled in the intestine to the liver in the hepatic portal vein
how does albumin maintain osmotic pressure
helps maintain colloid osmotic pressure which is a form of osmotic pressure caused by proteins that can pull water into the circulatory sys
reduction in plasma proteins = reduction of osmotic pressure = fluid retention issues
what can an abnormal synth of albumin be related to
hereditary defects, liver disease, malnutrition, malabsorptive disease
what can an abnormal distribution of albumin cause
capillary permeability leakage of proteins into extravascular fluid
what is an a1 globulin example
a1-anti-trypsin
what can be caused by homozygous alleles coding for a1-anti-trypsin
pulmonary emphysema(80% incidence), hepatic disorders
what can a1-anti-trypsin deficiency cause
cause 5% of emphemysa, whic is associated with lung infections and causes activity of macrohpages- leading to them producing elastase that damages the lung tissues
how can a1-anti-trypsin affect the liver
forms aggregates to form polymers which cause liver damage as well as an accumulation of collagen causing cirrhosis
write note on a2-macroglobulin
is a major a2 globulin, it binds and inactivates endopeptidases like trypsin, and can be seen increased in nephrotic syndrom and sometimes in cirrhosis
write a note on haptoglobulins
binfs Hb to form HbHp complexes. conserves iron stores in body. has decreased levels in intravascular haemolysis and liver disease. increased in acute infections and nephrotic syndrome
write a note on caeuroplasmin
is a copper transport protein, binds around 90% of copper. is reduced in wilson’s disease, malnutritin and nephrotic syndrome
see increased levels in pregnancy and in women taking birth control
write a note on a - fetoprotein
helps detect potential miscarraige in pregnancy. presnet in tissue and plasma of foetus. can detect minute amounts in adults via sensitive immunoassays
50% cases of heptocellular carcinoma have gross increases of FP levels
write a note on transferrin
is the principal plasma transport protein for iron.
congenital deficiency of transferrin = atransferrinaemia
where is low transferrin seen
inflammation and malignancy
where is increased transferrin seen
in iron deficiecny
write a note on complement proteins
has at least 20 proteins in blood and tissue fluids. these proteins interact:
- sequentially with Ag-Ab complexes
- with one another
- with cell membranes
in order to destroy viruses and bacteria
what are immuno globulins
structurally related plasma proteins that function as antibodies
where are immunoglobulins synthesised
cells of the lymphoreticular system
how are immunoglobulins classed
according to heavy chains: gamma, alpha, mu, delta and epsilonwh
what are the light chains in Ig
kappa and lambda
function of IgG, IgA, IgM, IgD, IgE
IgG: secondary immune response
IgA: submucus secretions
IgM: primary response
IgD: on B lymphocytes- antigen recognition
IgE: on mast cells and basophils -allergies
write a note on paraproteins
found in myeloma, waldenstrom’s macroglobulinaemia and heavy chain diseases (malignant diseases)
can arise from any Ig types. monoclonal light chains are made in excess of heavy chain in 50% of myeloma and in 15% cases only light chains are found
the light chains spill in urine- known as Bence Jones protein- do not show in serum electrophoresis - may need to do urine tests to demonstrate the protein
how can paraproteinaemia be diagnosed
serum protein electrophoreseis- detection of discrete band -> immunoelectrophoresis to determine paraprotein type and conc
urine protein electrohporesis -> detection of bence jones protein
