Plasma proteins

DR NILESH KATE
MBBS,MD
ASSOCIATE PROF
DEPT. OF PHYSIOLOGY
PLASMA
PROTEINS.

OBJECTIVES
 Plasma
 Composition
 serum
 Plasma proteins.
 Classification
 Methods of separation.
 Properties.
 Features.
 Functions.
 Synthesis
 Changes in health and
diseases.
Tuesday, February 2, 2016

Plasma.
 Composition.
 Water (91%)
 Solids. (9%)
 Plasma proteins.
 Organic molecules.
 Inorganic molecules.
 Gases.
 Clear straw coloured
fluid portion of blood
minus its cellular
elements. (55%)

Solids. (9%)
 Plasma proteins – 7%
 Normal range – 6.4-8.3gm%
 Albumin, globulin, fibrinogen
& others.
 Organic molecules
 Carbohydrates
 Fats
 Non-protein nitrogenous
substances
 Hormones.
 Inorganic
substances – 1%
 Na, K, Ca, Mg, Cl, I, Fe,
P & Cu.
 Gases.
 Oxygen, Co2 & N.

Serum.
 Blood allowed to clot
& clot retracted
remaining fluid is
serum.
 So serum is plasma
without fibrinogen &
clotting factors (II,V
&VIII)

Classification of plasma
proteins.
 Albumin
 Globulin.
 α1
 α2
 β
 γ
 Fibrinogen.

Methods of separation.
 Precipitation by salting out.
 Cohn’s fractional
precipitation method.
 Electrophoresis separation
of protein fractions.
 Immunoelectrophoresis
technique.
 Ultra-centrifugation
technique.

Precipitation by salting out.
 By sodium sulphate
solution.
 By Howe (1922).
 3 major fractions
 Fibrinogen – removed with
clot converting plasma into
serum.
 Globulins – by 22% Na2so4
 Albumin –m remains in
serum.
 By ammonium
sulphate solution.
 Albumin precipitated
by full saturation.
 Globulin – by half
saturation.
 Fibrinogen by one-
fifth saturation.

Cohn’s fractional precipitation
method.
 Ethanol solution with
different conc. at
lower temp is used to
fractionalize plasma
proteins
 Fraction I – rich in fibrinogen.
 Fraction II- gamma globulins.
 Fraction III – alpha & beta
globulin with isoagglutinin &
prothrombin.
 Fraction IV - alpha & beta
globulin.
 Fraction V – rich in albumin.

Electrophoresis separation of
protein fractions.
 It separate plasma proteins
into different fractions due to
electric charges of each
fractions.
 Clinical use –
 To know presence of abnormal
proteins
 Absence of normal proteins
 Change in relative conc. of
different proteins
 Techniques – (FPAC)
 Free boundary
electrophoresis.
 Paper electrophoresis.
 Agar gel
electrophoresis.
 Cellulose strip
electrophoresis.

Immunoelectrophoresis
technique.
 It uses antigenecity &
electric charge to
separate them.
 Proteins separated on
Electrophoretic
pattern by
precipitation at site of
Ag-Ab reaction.

Ultra-centrifugation
technique.
 Plasma proteins in
buffered solutions are
centrifuged at 60,000
rpm.
 Separated due to
sedimentation
constant by property
of weight, shape &
density.

Properties of plasma proteins.
 Molecular weight.
 Osmotic pressure.
 Specific gravity.
 Isoelectric point.
 Electrophoretic
mobility.
 Precipitation by salts.
 Water solubility.
 Amphoteric nature.

Molecular weight.
 Albumin – 69000
 Globulin – 90000-
156000
 Fibrinogen – 5,00,000

Osmotic pressure.
 25 mm of Hg.

Specific gravity.
 1.026

Isoelectric point.
 Can ionize either as acid
or base due to side
chain – amino group
(NH2) and carboxyl
group (-COOH).
 pH at which it carries
equal positive &
negative charges is
Isoelectric point.

Electrophoretic mobility.
 Act as Anion in
alkaline solutions &
Cation in acidic
solution.

Precipitation by salts.
 This property of
proteins is utilized for
their separation by
precipitation method.

Water solubility.
 Due to the presence of
polar residue like NH2
& COOH they are
water soluble.

Amphoteric nature.
 Again due to their
presence of NH2 &
COOH groups.
 They are Amphoteric in
nature.
 So are efficient buffers.

Features of plasma proteins.
Plasma
proteins.
Plasma
levels
Molecular
wt.
Synthesis. Half life.
Albumin 4.8 gm% 69000 Liver 10 days
Globulin. 2.3 gm % 90000-
156000
Liver
Fibrinogen. 0.3 gm% 400000-
500000
Liver
Prothrombin
.
40 mg% 68000 Liver

Different forms of Globulins.
 Ceruloplasmin.
 Fetunin.
 Glycoprotein.
 Haptoglobulin.
 Angiotensinogen.
 Transferrine.
 Immunoglobulin.
 Lipoproteins.
 Haemagglutinins.

Functions of Plasma Proteins.
 Suspension stability of
blood.
 Fibrinolytic function.
 Osmotic pressure.
 Blood viscosity.
 Coagulation of blood.
 Defense mechanism of
body.
 Transport function.
 Reserve proteins.
 Acid base balance of
the body.
 Nourishment of tissue
cells.
 Genetic information

Suspension stability of blood.
 It’s the property of
RBC due to which they
remain suspended.
 Globulin & fibrinogen
– mainly responsible.

Fibrinolytic function.
 Digest intravascular
clot ( Thrombus)
 Save from
intravascular
thrombosis.

Osmotic pressure.
 Mainly proteins can't
pass through capillary
membrane so exert
osmotic pressure.
 About 25 mmHg.
 70-80% due to
albumin.
 Imp for exchange of
fluids.
 At Arterial end
 At Venous end.

Blood viscosity.
 Due to size & shape of
plasma proteins.
 Mainly fibrinogen &
globulins due to its
asymmetrical shape.
 viscosity
resistance
 Blood pressure.

Coagulation of blood.
 Mainly fibrinogen,
Prothrombin and other
coagulation proteins.

Defense mechanism of body.
 Mainly gamma
globulins against
microorganisms.

Transport function.
Sr no COMOUND TRANSPORTER
1 CO2 AS CARBAMONO COMPOUND
2 THYROXINE THYROXINE BINDING PROTEIN.
3 CORTISOL TRANSCORTIN.
4 VIT A,D,E HDL,LDL
5 BILIRUBIN ALBUMIN
6 VIT B12 TRANSCOBALAMINE
7 DRUGS ALBUMIN
8 COPPER CERULOPLASMIN
9 FREE HAEMOGLOBIN HAPTAGLOBIN

Reserve proteins.
 Utilized by body tissue
during conditions like
 Fasting
 Inadequate protein
intake
 Excessive catabolism of
body proteins.

Acid base balance of the body.
 Contribute 15% of
total buffering
capacity of blood.
 In acidic pH NH2 acts
as base & accepts
proton
 In basic pH – COOH
acts as acid & donate
proton.

Nourishment of tissue cells.
 Plasma proteins used
by WBC to produce
substances known as
Trephones or Carrel.
 Essential for
nourishment of tissue
cells.

Genetic information
 Plasma proteins exhibit
polymorphism.
 It’s a Mendelian Trait.
 Valuable tool for
population genetics study.
 Mainly haptoglobin,
immunoglobulin,
ceruloplasmin &
transferrin.

Synthesis of plasma proteins.
 Site.
 In embryo – Mesenchymal cells.
 In Adult –
 Albumin & Fibrinogen by retculoendothelia cells of liver.
 Alpha & beta globulins by liver, spleen & bone marrow.
 Gamma by B Lymphocytes.

Factors affecting Synthesis of
plasma proteins.
 Dietary proteins.
 Relationship between dietary proteins & plasma
proteins is studied by “Whipple” by experiment
called “Plasmapheresis”.

Plasmapheresis.
 Dog made
hypoproteinemic by
repeatedly withdrawing
blood & reinjecting
cellular elements.(in
Ringer Locke RL) till
protein 4gm/100ml.
 Then different standard
diets are given

Conclusions.
 Dietary proteins – essential.
 Chemical resemblance – determine efficacy.
 Essential amino acids – must for synthesis.
 Dietary proteins of animal origin – favors
albumin synthesis.

Conclusions.(cont….)
 Dietary proteins of plant origin - Globulin
synthesis.
 Regeneration period – 14 days.
 Rate of regeneration – very fast within first 24
hrs.

Other factors.
 Presence of infection. –
reduces plasma protein
synthesis.
 Exposure to antigen –
stimulate formation of
antibodies.
 Inflammatory
conditions – promotes.
 Colloid oncotic pressure
affects albumin synthesis.
 Interleukin I by
activated
macrophages
stimulate synthesis.
 Prostaglandins –
increases acute phase
proteins.

Changes in plasma proteins in
health & disease.
 Normal levels.
 Total Proteins – 7.4gm%
 Albumin – 4.8 gm%
 Globulin – 2.3 gm%
 Albumin/globulin ratio. – 1.7:1

Abnormalities.
 Hypoproteinemia –
decreased levels.
 Effects –
 Decreased plasma
osmotic pressure.
 Water retention.
 Oedema of body tissue.

Causes –
Dietary deficiency.
Malabsorption syndrome.
Liver diseases.
Renal diseases.
Hemorrhage & extensive burns.
Hereditary analbuminaemia
Congenital afibrinogenemia.

Abnormalities.
 Hyperproteinemia –
increased levels.
 Causes –
 Acute inflammatory
conditions increases acute
phase proteins.
 Acute tissue destruction -
MI
 Chronic inflammation &
malignancies – raises C
reactive proteins.
 Multiple myeloma- raises
Bence Jones proteins.

Reversal of normal A:G ratio.
 Normal ratio 1.7:1
 Reversed in
 Liver diseases as albumin synthesis decreases.
 Hypoproteinemia as globulin levels increases.

Plasma proteins

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