L3: Plasma proteins Flashcards
What is the composition of plasma?
Water: 90 %
Inorganic substances: 0.9%
- Cations: Na+ / K+
- Anions: Cl / HCO3 / PO4 / SO4
Organic substances: 9.1 %
- Plasma proteins: (6-8 gm%) (6-8GM/DL)
- Lipids
- Others
What is the level of total proteins in plasma?
about 7-7.5 g/dl. “dl=100ml”
What is the composition of plasma proteins?
Plasma proteins include not only simple proteins but also conjugated proteins as glycoproteins and lipoproteins.
What are the types of plasma proteins?
Plasma proteins can be classified into 3 main groups: albumin, globulins (α1, α2, β and y ) and fibrinogen.
Where are plasma proteins synthesized?
Most plasma proteins are synthesized in the liver. However, Y globulins “antibodies” are synthesized by plasma cells and B cells of lymphoid tissues.
What is the definition of albumin and what is its levels in blood?
- Is the major human plasma protein (60% of total plasma protein).
- 3.5-5.5 g/dl
What are the functions of albumin?
“Osmotic pressure - carrier - treatment of hemorrhage and burns”
- Responsible for 70 to 80% of osmotic pressure of human plasma.
- Helps in transport of several substances e.g., FFA, unconjugated bilirubin, Ca++ and steroid hormones”also carried by globulins”.
- Certain drugs also bind to albumin, e.g., sulphonamides, aspirin, penicillin and are transported to target tissue.
- Preparations of human albumin have been widely used in treatment of hemorrhagic shock and burns.
What are alpha-1 globulins? “Markers”
α1-acid glycoprotein (orosomucoid)
α1-antitrypsin (α- AT)
What is the function of alpha 1 - acid Glycoproteins (Orosomucoid)?
A reliable indicator of acute inflammation. “Its increase”
What is the function of alpha 1 - antitrypsin?
It is the principal protease inhibitor (Pi) of human plasma: It inhibits trypsin, elastase and other proteases by forming complexes with them.
- It is deficient in emphysema.
What are alpha-2 globulins? “Carriers”
Haptoglobin
What is the function of haptoglobulin?
- Bind free Hb and minimizes urinary loss of Hb.
- After binding, Hp-Hb complex circulates in the blood,
which cannot pass through glomerular filter and ultimately the complex is destroyed by RE cells.
What are beta globulins?
β- Lipoproteins (LDL) “bad”
Transferrin “carrier”
C-reactive Protein
What is the function of transferrin?
transport of Fe between intestine and site of synthesis of Hb and other Fe containing proteins.
What is the function of C-reactive proteins?
- It precipitates with group C polysaccharide of pneumococci, in the presence of Ca, hence the name.
- It can bind to T-lymphocytes and can activate complement.
- Used as a marker of tissue injury & inflammation.
What are gamma globulins?
These are immunoglobulins having antibody activity.
What is fibrinogen?
- also called clotting factor I,
- as it takes part in coagulation of blood.
What are the functions of plasma proteins?
Nutritive Fluid exchange (colloid osmotic pressure) Buffering action Binding and transport function Blood coagulation and fibrinolysis Immunological function Enzymes Carriage of CO2
What is the nutritive function of plasma proteins?
contribute amino acids for tissue protein synthesis.
How do plasma proteins affect fluid exchange?
Regulation of blood volume and tissue fluid formation: plasma proteins exert osmotic pressure across the capillary wall which tend to pull water into the blood.
What is the buffering action of plasma proteins?
The serum proteins, like other proteins, are amphoteric, they have free acidic (R-COOH) and basic (R-NH2) end so can act as weak acid or base and thus can combine with acids or bases.
What do plasma proteins transport?
✓ Albumin → binds various ligands (thyroxine, steroids, a a, vitamins and FA).
✓ Haptoglobin→binds extra corpuscular HB
✓ Apolipoproteins → Lipoproteins
✓ Thyroid-binding globulin → binds T3 & T4
✓ Transferrin → transports iron.
✓ Ceruplasmin → copper
✓ Steroid hormone – binding globulin → steroid hormone
✓ Transcobalamin→vit B12 “cobolamin”
What is the Immunological function of plasma proteins?
Y-globulins protect the body against microbial infections.
What is the enzymatic function of plasma proteins?
Enzymes are proteins.
