Plasma proteins are synthesized in the liver and include albumin, globulin, and fibrinogen, each playing crucial roles in various bodily functions such as maintaining colloid osmotic pressure, transporting substances, and aiding in blood coagulation. Dietary proteins and certain physiological conditions significantly affect the synthesis of these proteins, with deficiencies leading to hypoproteinaemia and excesses resulting in hyperproteinaemia. The document elaborates on the importance of plasma proteins in fluid balance, immunity, and metabolic processes.

1. PLASMA PROTEINS

2. These are the proteins present in plasma.
They are synthesized in the liver .

3. The major forms of plasma proteins:
1. Albumin
2. Globulin
3. Fibrinogen

4. Albumin:
M.W. 69,000.
Plasma concentration : 3.5-5.5gm%
Globulin:
Subtypes:
alpha1 , alpha2 , beta and gamma.
M.W. 90,000-1,50,000.
Plasma concentration : 2-3.5gm%
Fibrinogen:
M.W. 5,00,000 .
Plasma concentration : 0.3gm%

5. • Alpha1globulin : alpha-1-antitrypsin ,
transcortin .
• Alpha2globulin :haptoglobin ,
ceruloplasmin , alpha-2-macroglobulin .
• Betaglobulin : plasminogen , transferrin ,
sex hormone binding globulin ,
beta-2-microglobulin .

6. The total plasma protein concentration :
6.4-8.3gm% . ( Avg. 7.4gm% )
Albumin is most abundant .
A/G ratio = 1.7:1

7. Forms of globulin:
1.Glycoprotein: contains carbohydrate.
2. Lipoprotein: contains lipid.
3. Transferrin: binds to (Fe3+) ferric ions.
4. Haptoglobin: binds to free hemoglobin.

8. 5. Ceruloplasmin: binds to copper.
6. Angiotensinogen
7. Erythropoetinogen
8. Haemagglutinins: antibodies against
red cell antigens.
9. Immunoglobulins

9. 10. Trancortin binds to cortisol ,
aldosterone , progesterone .
11. Sex hormone binding globulin binds
to testosterone , estrogen .

10. Functions of plasma proteins:
1.Help to maintain the plasma colloid
osmotic pressure
Plasma proteins are unable to pass
across the capillary wall
and consequently exert
colloid osmotic pressure .

11. Colloid osmotic pressure is
inversely proportional
to the molecular weight and
directly proportional
to the concentration of the protein .
Albumin is responsible for 75% of the
plasma colloid osmotic pressure because
of its least molecular weight and
maximum concentration.

12. The plasma colloid osmotic pressure
is one of the forces influencing
the process of tissue fluid formation.

13. 2.Transport function :
Plasma proteins combine easily with many
substances
and play an essential role in their transport .
Carbon dioxide is transported in the form of
carbamino compound .
Thyroxine – albumin
Cortisol – transcortin .

14. Vitamin A,D & E – lipoproteins
Vitamin B12 - transcobalamin
Unconjugated bilirubin – albumin
Drugs – albumin
Calcium – albumin
Copper- ceruloplasmin
Free haemoglobin – haptoglobin

15. 3. Role in coagulation of blood –
Fibrinogen and other coagulation factors .
4. Contribution to blood viscosity -
Blood viscosity is one of the factors
influencing peripheral resistance and
thereby the arterial blood pressure .

16. 5. Role in defense mechanism of the body –
gamma globulins are antibodies .
6. Role in maintaining the
acid-base balance of the body -
Plasma proteins act as buffers
and
contribute about 15 %
of the buffering capacity of blood .

17. In acidic pH ,
the NH2 group of the proteins
acts as base and
accepts a proton .
In alkaline pH ,
the COOH group of the proteins
acts as acid and
donates a proton .

18. 7. Role as reserve proteins –
utilized by the tissues during starvation .
8. Role in suspension stability of RBCs –
RBCs remain uniformly suspended in
the blood .
9. Fibrinolytic function – The enzymes
digest the intravascular clot ( thrombus ).

19. Factors affecting synthesis
of plasma proteins :
1. Dietary proteins : The relation of plasma
proteins to diet was studied in plasma
protein depleted animal by an experiment
procedure called plasmapheresis .
In this experiment , the animal is rendered
hypoproteinaemic by repeatedly withdrawing
whole blood and injecting back the cellular
elements of blood suspended in Ringer-
Locke solution .

20. This process is repeated daily till the level of plasma
proteins falls to 4gm% .
Thereafter different standard diets are given and
their effects on protein synthesis are studied .
Following conclusions have been drawn :
1. Dietary proteins are essential for synthesis of
plasma proteins .

21. 2. Chemical resemblance of food protein amino acids
with those of the plasma protein to be synthesized
determine the efficacy of the diet to synthesis of a
particular protein .
3.Essential amino acids must be present in the diet for
the satisfactory synthesis of plasma proteins .
4.Dietary proteins of animal origin favour albumin
synthesis .

22. 5. Dietary proteins of plant origin favour globulin
synthesis .
6. Regeneration of plasma proteins occurs
within 14 days .
7. Rate of regeneration of plasma proteins
is very fast within first 24 hours .

23. 2.Other factors :
Inflammatory conditions promote the synthesis
of a number of proteins .
Exposure to some antigen stimulates
formation of antibodies .
Interleukin -1 released by the activated macrophages
stimulates the synthesis of many acute phase proteins in
the liver .

24. Acute phase proteins :
D-dimer protein , C-reactive protein ,
Alpha-1-antitrypsin , Coagulation factors ,
Ferritin , Ceruloplasmin ,Complement
factors , Haptoglobin , Alpha-2-
macroglobulin

25. Physiological variations :
In infants , the total protein level is low
(about 5.5gm% ) due to
low gamma globulins .
In old age there is a tendency for the albumin
level to fall and the globulin level to rise .
In pregnancy , the albumin and globulin levels
decrease while the fibrinogen level increases

26. Hypoproteinaemia :
Dietary deficiency
Malabsorption syndrome
Liver disease – cirrhosis
Renal disease – nephrotic syndrome
Hemorrhage
Burns

27. Hypoproteinaemia is associated with
decrease in plasma colloid osmotic pressure
which causes abnormal rise in
interstitial fluid volume ( edema ) .

28. Hyperproteinaemia :
is seen in acute & chronic inflammation ,
myocardial infarction ,malignancies and
multiple myeloma .
Dehydration can manifest with
hyperproteinaemia .

29. Reversal of normal A/G ratio : occurs
• when the albumin synthesis is decreased
as occurs in liver disease .
• when albumin levels fall and globulin
levels rise in conditions associated with
hyperproteinaemia .