DR NILESH KATE

MBBS,MDASSOCIATE 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.

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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%)

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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.

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Serum. Blood allowed to clot

& clot retracted remaining fluid is serum.

So serum is plasma without fibrinogen & clotting factors (II,V &VIII)

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Classification of plasma proteins.

Albumin Globulin.

α1 α2 β γ

Fibrinogen.

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Methods of separation. Precipitation by salting out. Cohn’s fractional

precipitation method. Electrophoresis separation of

protein fractions. Immunoelectrophoresis

technique. Ultra-centrifugation

technique.

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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.

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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.

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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.

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Immunoelectrophoresis technique.

It uses antigenecity & electric charge to separate them.

Proteins separated on Electrophoretic pattern by precipitation at site of Ag-Ab reaction.

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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.

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Properties of plasma proteins. Molecular weight. Osmotic pressure. Specific gravity. Isoelectric point.

Electrophoretic mobility.

Precipitation by salts. Water solubility. Amphoteric nature.

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Molecular weight. Albumin – 69000 Globulin – 90000-

156000 Fibrinogen – 5,00,000

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Osmotic pressure. 25 mm of Hg.

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Specific gravity. 1.026

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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.

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Electrophoretic mobility. Act as Anion in

alkaline solutions & Cation in acidic solution.

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Precipitation by salts. This property of

proteins is utilized for their separation by precipitation method.

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Water solubility. Due to the presence of

polar residue like NH2 & COOH they are water soluble.

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Amphoteric nature. Again due to their

presence of NH2 & COOH groups.

They are Amphoteric in nature.

So are efficient buffers.

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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

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Different forms of Globulins. Ceruloplasmin. Fetunin. Glycoprotein. Haptoglobulin.

Angiotensinogen. Transferrine. Immunoglobulin. Lipoproteins. Haemagglutinins.

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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

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Suspension stability of blood. It’s the property of

RBC due to which they remain suspended.

Globulin & fibrinogen – mainly responsible.

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Fibrinolytic function. Digest intravascular

clot ( Thrombus) Save from

intravascular thrombosis.

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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.

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Blood viscosity. Due to size & shape of

plasma proteins. Mainly fibrinogen &

globulins due to its asymmetrical shape.

viscosityresistance Blood pressure.

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Coagulation of blood. Mainly fibrinogen,

Prothrombin and other coagulation proteins.

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Defense mechanism of body. Mainly gamma

globulins against microorganisms.

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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

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Reserve proteins. Utilized by body tissue

during conditions like Fasting Inadequate protein

intake Excessive catabolism of

body proteins.

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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.

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Nourishment of tissue cells. Plasma proteins used

by WBC to produce substances known as Trephones or Carrel.

Essential for nourishment of tissue cells.

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Genetic information Plasma proteins exhibit

polymorphism. It’s a Mendelian Trait. Valuable tool for

population genetics study. Mainly haptoglobin,

immunoglobulin, ceruloplasmin & transferrin.

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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.

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Factors affecting Synthesis of plasma proteins.

Dietary proteins. Relationship between dietary proteins & plasma

proteins is studied by “Whipple” by experiment called “Plasmapheresis”.

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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

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

albumin synthesis.

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Conclusions.(cont….) Dietary proteins of plant origin - Globulin

synthesis. Regeneration period – 14 days. Rate of regeneration – very fast within first 24

hrs.

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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.

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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

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Abnormalities. Hypoproteinemia –

decreased levels. Effects –

Decreased plasma osmotic pressure.

Water retention. Oedema of body tissue.

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

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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.

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Reversal of normal A:G ratio. Normal ratio 1.7:1 Reversed in

Liver diseases as albumin synthesis decreases. Hypoproteinemia as globulin levels increases.

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Thank You