Monday, October 22, 2012

Plasma proteins

GroupProteinFunctionClinical Significance
Albuminsa) Albumin

b) Transthyretin
a)Maintenance of osmotic pressure;  transport of fatty acids, bilirubin, bile acids, steroid hormones, pharmaceutical drugs, inorganic ions; buffering and nutritive.

b)Transport of thyroxin, triiodothyronin and retinol

a)Hypoalbuminemia-Liver cirrhosis, protein energy malnutrition, mal absorption, nephrotic syndrome, protein losing enteropathy, extensive skin burns, genetic disease- Analbuminemia, Hemodilution

b) Concentration decreased in all conditions of hypoproteinemia and during infections (Negative acute phase protein)
α1-Globulinsa) Antitrypsin

b)  Antichymotrypsin

c) Lipoprotein (HDL)

d) Prothrombin

e) Transcortin

f) Acid glycoprotein

g) Thyroxin-binding globulin


a) Inhibition of Trypsin and other proteases

b) Inhibition of Chymotrypsin

c) Transport of  cholesterol from tissues to liver

d) factor II, thrombin precursor

e) Transport of cortisol, corticosterone and progesterone

f) Transport of progesterone

g) Transport of iodothyronins

h) Present in fetal blood

a) Acute phase protein (concentration rises  during infections), deficiency associated with Emphysema and liver cirrhosis and acts as a tumour marker- increased level in germ cell tumours of testes and ovaries.


c) Cardio protective


e) Concentration increases during pregnancy.

f)Acute phase protein

g) Level – Low in Nephrotic syndrome,
High –during pregnancy

h) Tumor marker- High concentration in Hepatocellular malignancies
α 2-Globulinsa) Ceruloplasmin

b) Antithrombin III

c) Haptoglobin

d) Cholinesterase

e) Plasminogen

f) Macroglobulin

g) Retinol-binding protein

h) Vitamin D-binding protein
a)Transport of copper ions, ferroxidase and Histaminase activities

b) Inhibition of blood clotting

c) Binding of hemoglobin

d) Cleavage of choline esters

e) Precursor of plasmin breakdown
of blood clots

f) Binding of proteases, transport of zinc ions

g) Transport of vitamin A

h) Transport of Calcitriol

a) Acute phase protein, Low levels in Wilson disease and Menke’s disease.


c) Acute phase protein,Low level in Haemolytic diseases.


f) Low level in Nephrotic syndrome

g) Level of retinol binding protein indicates vitamin A status.

h) Low level in Nephrotic syndrome and PEM

a) Lipoprotein (LDL)


c) Haemopexin

d)Sex hormone binding

e) Transcobalamine

f) C-reactive protein 
a) Transport of lipids

b) Transport of iron ions

c) Binds fee haem

d) Transport of testosterone and estradiol

e) Transport of vitamin B12

f) Complement activation
a) Atherogenic (Bad cholesterol)

b) Negative acute phase protein, low level in all conditions of hypoproteinemia
High levels in iron deficiency anemia
c)Decreased level in Hemolytic disorders

f)Acute phase protein
a) IgG

b) IgA

c) IgM

d) IgD

e) IgE

a) Main antibody in the secondary response, Opsonizes bacteria, making them easier to phagocytose. Fixes complement, which enhances bacterial killing. Neutralizes bacterial toxins and viruses. Crosses the placenta.

b) Mucosa-protecting antibodies
Secretory IgA prevents attachment of bacteria and viruses to mucous membranes. Does not fix complement.

c) Produced in the primary response to an antigen. Fixes complement. Does not cross the placenta. Antigen receptor on the surface of B cells.

d) B-lymphocyte receptors

e) Mediate immediate hypersensitivity by causing release of mediators from mast cells and basophils upon exposure to antigen (allergen).
Defend against worm infections by causing release of enzymes from eosinophils.
Does not fix complement.
Main host defense against helminthic infections.
High concentration in  chronic infections, chronic liver diseases, Sarcoidosis, Autoimmune diseases, Multiple myeloma and lymphoreticular malignancies

Low concentration in immunodeficiency disorders.

c) High concentration  of Ig M -in Waldenstrom’s Macroglobulenemia

e) High concentration in allergic disorders and helminthic infections.

------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123, ------------------------------------------
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