1. FUNCTIONS OF PLASMA PROTEINS
Dr. B. L. Mtinangi
Department of Physiology
University of Dar es Salaam
November, 2015

2. PLASMA Is an extracellular fluid in the INTRAVASCULAR compartment
A straw coloured fluid at the top after centrifugation of uncoagulated blood
Contain 7% protein
Normal total plasma protein is about 7-7.5g/dl and Albumin is about 4.8gm%, Globulin-2.3gm%, Fibrinogen- 0.3gm% & Protrombin 0.03gm%

3. PLASMA COMPOSITION Water is about 91% to 92%
Inorganic substances Na+, Ca2+ Cl-,K+ etc
Organic substances like Amino acids ( AA), Glucose, Free Fatty Acids etc
Internal secretion like hormones, enzymes, antibodies etc

4. SERUM
Serum is a clear fluid from the clotted blood ie Plasma without some clotting factors or
A clear fluid at the top after centrifugation of coagulated blood

5. SOME SPECIFIC FUNCTIONS OF PLASMA PROTEINS
Maintainance of Colloid Osmotic Pressure ie Plasma Colloid Osmotic Pressure especially albumin (PCOP)
Maintainance of PH and electrolytes balance
Transport of metal ions e.g copper, iron etc.
Transport of fatty acids, Steroids, hormones & drugs

6. COMPOSITION OF PLASMA PROTEIN
Plasma protein is mainly composed of:
Albumin for Plasma colloidal osmotic pressure (PCOP)
Fibrinogen and other clotting factors like prothrombin etc
Globulins: subtypes alpha1 & 2, beta 1 & 2, and gamma globulins for body immunity

7. METHODS OF PLASMA PROTEIN SEPARATION
COMMON METHODS of protein separation into albumin, fibrinogen, alpha, beta and gamma globulins
Paper electrophoresis
Ultracentrifugation
Affinity chromatography
Fractional precipitation method
Immune electrophoresis

8. SEPARATION CONT.
For example Electrophoresis separation pattern depends on:
Size
Shape
Composition
Physiological function of each
plasma protein

9. SPECIFIC PLASMA PROTEIN
Plasma Albumin.
Forms 60% total plasma proteins
Normal value 3.4 to 4.5g/dl
Responsible for 80% PCOP
Acts as a carrier of e.g bilirubin and drugs
Synthetized in the liver
Molecular Weight (MW)

10. PLASMA GLOBULINS
Plasma Globulins stands for alpha1, alpha2, beta and gammaglobulins.
alpha1 globulins is a glycoprotein which binds two thirds of glucose.
Alpha2 globulins consists of haptoglobin which binds free haemoglobin and ceruloplasmin which binds copper
Beta globulins has MW 90,000

11. GLOBULINS CONT.
beta globulins is a lipoprotein a protein that carries LIPIDS (75%) and polysaccharides.
It also binds and transport IRON
gamma globulins (MW 156,000) it is for IMMUNOGLOBULINS (antibodies ) ie it is responsible for body protection and defence

12. FIBRINOGEN Fibrinogen: Is a plasma clotting factor
Manufactured in the liver
Normal value is 4% to 6% of total plasma protein

13. SUMMARY OF PLASMA PROTEINS
Exerts Colloid Osmotic Pressure
Viscosity of blood ie 50% is due to plasma proteins and 50% due to Rbcs
Role in coagulation of blood
Acts as buffers ie contribute 15% of the buffering power of blood
Transport function ie Oxygen combines with haemoglobin & CO2 combines with plasma proteins
Defence function eg gamma globulins

14. Thank you