Transcript Document
FUNCTIONS OF PLASMA
PROTEINS
Dr. B. L. Mtinangi
Department of Physiology
University of Dar es Salaam
November, 2015
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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 77.5g/dl and Albumin is about 4.8gm%,
Globulin-2.3gm%, Fibrinogen- 0.3gm%
& Protrombin 0.03gm%
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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
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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
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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
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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
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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
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SEPARATION CONT.
For example Electrophoresis
separation pattern depends on:
Size
Shape
Composition
Physiological function of each
plasma protein
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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). 69000
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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
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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
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FIBRINOGEN
Fibrinogen:
Is a plasma clotting factor
Manufactured in the liver
Normal value is 4% to 6%
of total plasma protein
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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
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Thank you