Amino acids are a group of organic compounds containing two functional groups amino and carboxyl. The amino group (-NH2) is basic while the carboxyl group (-COOH) is acidic in nature. The plasma in the liquid medium of blood (55%) in which the cell components namely Erythrocytes, Leucocytes and Platelets are suspended.  If anticoagulated blood is centrifuged, the plasma separates out as a supernatant while the cells remain at the bottom.  Plasma consists of water electrolytes metabolites nutrients proteins and hormones.  Most of the plasma proteins are synthesized in the liver.  Plasma proteins are separated by electrophoresis.

1. Tapeshwar Yadav
(Lecturer, MBAHS)
BMLT, DNHE,
M.Sc. Medical Biochemistry
&
Clinical Diagnostic Laboratory
Incharge
(Hetauda Hospital)
Basics of Amino Acids &
Plasma Proteins

2. Student Learning Outcomes
At the end of the lecture students will be able to:
 Define Amino Acids
 Classification of Amino Acids
 Define Plasma Proteins
 Functions of Plasma Proteins
 Classification of Plasma Proteins in brief

3. Definition
Amino acids are a group of organic
compounds containing two functional
groups amino and carboxyl. The amino
group (-NH2) is basic while the carboxyl
group (-COOH) is acidic in nature.

4. General structure of amino
acids:
Each amino acid has an amino group –NH2, carboxylic acid –
COOH, hydrogen –H and R- side chain (hydrogen, aliphatic,
aromatic or hetero cyclic group).

5. Classification of amino acids
A. Based on structure: The amino acids in
protein can be divided into 7 classes as
 I. With aliphatic side chains: Glycine, Alanine,
Valine, Leucine & Isoleucine.
 II. With side chain containing hydroxyl (OH) group:
Serine & Threonine.
 III. Sulphur containing amino acids: Cysteine &
Methionine.
 IV. Acidic amino acids and their amides: Aspartic
acid, Glutamic acid, Asparagine & Glutamine.

6. Contd…
 V. Basic amino acids: Lysine, Arginine & Histidine.
 VI. Aromatic amino acids: Phenylalanine, Tyrosine &
Tryptophan.
 VII. Imino acids: Proline.
{Code for remember: GAVLI, ST, CM, AG-AG, LAH,
PTT, P}
Note: As already stated, 20 aminoacids are commonly
found in proteins. In recent years, a 21st aminoacid
namely selenocysteine has been added.
 In the year 2002, some researchers have described yet
another aminoacid namely pyrrolysine as the 22nd

7. B. Based on nutritional
requirement:
I. Essential amino acids: The amino acids which
cannot be synthesized by the body and, therefore,
need to be supplied through the diet are called
essential amino acids.
 - They are required for proper growth and
maintenance of the individual.
 - Normal growth and optimal health will not occur, if
one such amino acid is deficient in the diet.

8. Contd…
 The ten amino acids listed below are essential:
  Arginine  Valine
  Histidine  Isoleucine
  Leucine  Lysine
  Methionine  Phenylalanine
  Threonine & Tryptophan
{Code to remember: AV, HILL, MPT.T}
Note: The two amino acids namely arginine and
histidine can be synthesized by adults and not by
growing children, hence these are considered as semi-
essential amino acids. (recall HA).

9. Contd…
II. Non-essential amino acids:
 - The body can synthesize about 10 amino
acids to meet the biological needs, hence they
need not be consumed in the diet.
 - These are: Glycine, Alanine, Serine,
Cysteine, Aspartate, Asparagine, Glutamate,
Glutamine, Tyrosine and Proline.

10. C. Based on polarity: 4 groups
I. Non-polar amino acids:
 - These are hydrophobic (water hating) and carry
no charge on the ‘R’ group.
 - These includes: Alanine, Leucine, Isoleucine,
Valine, Methionine, Phenylalanine, Tryptophan and
Proline.

11. Contd…
II. Polar amino acids: with no charge on ‘R’-
group
 - These amino acids, as such, carry no charge
on the 'R'-group.
 - They however possess groups such as
hydroxyl, sulfhydryl and amide and participate in
hydrogen bonding of protein structure.
 - These includes: Glycine, Serine, Threonine,
Cysteine, Glutamine, Asparagine and Tyrosine.

12. Contd…
 III. Polar amino acid: with positive ‘R’-group:
Lysine, Arginine and Histidine.
 IV. Polar amino acid: with negative ‘R’-group:
Aspartic acid and Glutamic acid.

13. D. Based on their metabolic
fate:
  The carbon skeleton of amino acids serve as
a precursor for the synthesis of glucose
(glycogenic) or fat (ketogenic) or both.
  From metabolic point of view, it is divided into
3 groups:
 I. Glycogenic amino acids: These amino
acids can serve as precursors for the formation of
glucose or glycogen.
 e.g: Alanine, Aspartate, Glycine, Methionine
etc.

14. Contd…
II. Ketogenic amino acids: Fat can be
synthesized from these amino acids.
 e.g: Leucine &Lysine are exclusively
ketogenic
 III. Glycogenic and ketogenic amino acids:
These amino acids are precursors for synthesis of
glucose as well as fat.
 e.g: Isoleucine, Phenylalanine, Tyrosine
&Tryptophan,

16. PLASMA
PROTEINS

17. Introduction
 The plasma in the liquid medium of blood (55%)
in which the cell components namely
Erythrocytes, Leucocytes and Platelets are
suspended.
  If anticoagulated blood is centrifuged, the
plasma separates out as a supernatant while the
cells remain at the bottom.
  Plasma consists of water electrolytes
metabolites nutrients proteins and hormones.
  Most of the plasma proteins are synthesized
in the liver.
  Plasma proteins are separated by

18. Types:
The plasma proteins are:
 1. Albumin
 2. Globulin
 3. Fibrinogen

19. 1. Albumin:
  Major constituents (60%) of plasma proteins
  Molecular weight = 69000.
  Synthesized in liver.
  Liver produce 12 gm of albumin per day.
Functions:
  It maintains osmotic pressure.
  It has the maximum buffering capacity.
  It transports free fatty acids, bilirubin. Steroid
hormones, calcium copper etc.
  Albumin serves as a source of amino acids for
tissue protein synthesis.

20. Contd…
2. Globulin:
  It constituents several proteins that are separated
into 4 distinct bonds (α1, α2, β and γ-globulins).
  They perform variety of functions which include
immunity and transport.
3. Fibrinogen:
  It is soluble glycoprotein that constitutes 2-3% of
plasma proteins.
  It having role in blood clotting mechanism.

21. Normal Value:
 Total Protein: 6 – 8 gm/dl
 Albumin: 3.5 – 5.0 gm/dl
 Globulin: 2.5 – 3.5 gm/dl
 Fibrinogen: 0.2 – 0.4 gm/dl

22. Clinical Significance of Plasma
Protein:
 Various abnormalities can be identified in the
electrophoretic pattern:
 1. Chronic infections: The gamma globulins are
increased, but the increase is smooth and widebased.
 2. Multiple myeloma: In para-proteinemias, a
sharp spike is noted and is termed as M-band. This is
due to monoclonal origin of immunoglobulins in
multiple myeloma.
 3. Fibrinogen: Instead of serum, if plasma is used
for electrophoresis, the fibrinogen will form a
prominent band in the gamma region, which may be
confused with the M-band.
 4. Primary immune deficiency: The gamma

23. Contd…
 5. Nephrotic syndrome: All proteins except very
big molecules are lost through urine, and so alpha-2
fraction (containing macroglobulin) will be very
prominent.
 6. Cirrhosis of liver: Albumin synthesis by liver is
decreased, with a compensatory excess synthesis of
globulins by reticulo-endothelial system. So albumin
band will be thin, with a wide beta fraction; sometimes
beta and gamma fractions are fused.
 7. Chronic lymphatic leukemia, gamma globulin
fraction is reduced.
 8. Alpha-1-antitrypsin deficiency: The alpha-1
band is thin or even missing.

24. Fig: Normal and abnormal electrophoretic patterns

25. "Where there is a will, there is a way. If there is a
chance in a million that you can do something,
anything, to keep what you want from ending, do
it. Pry the door open or, if need be wedge your
foot in that door and keep it open."
Pauline Kael