Proteins, classification, amino acids, structure and uses.

1. Proteins and
Amino Acids
PREPARED BY SHRUTI TYAGI
M. Pharm Pharmaceutics
Lecturer in Pharmacy at B.S. Anangpuria Institute of
Pharmacy

2. Biochemistry
The science concerned with the chemical constituents of living cells and
with the reactions and processes they undergo.
Biochemistry
Clinical
Biochemistry
Nutritional
Biochemistry

3. Amino Acids
Amino acids are the organic acids containing at least one amino group
and one carboxylic acid group. Several units of amino acids combine to
form Proteins.

4. Classification of Amino Acids
AMINO ACIDS
On the basis of
Nutritional Status
On the basis of
Nature of solution
and Structure
Essential
AA:
Leucine
Non-
Essential
AA:
Proline
Basic AA:
Lysine
Sulphur
containin
g AA:
CysteineHeterocy
clic AA:
Proline
Neutral
AA:
Glycine
Acidic
AA:
Aspartic
Acid

5. PROLINE LEUCINE ASPARTIC ACID
LYSINE GLYCINE CYSTEINE

6. Proteins
These are the polymers of Amino Acids linked by peptide bonds.
Polypeptides: These are formed when several Amino Acids Combine with each other
through peptide bonds. These are smaller molecules as compared to proteins. Importance of
Proteins:
Enzyme:
Lactate Dehydrogenase,
which coverts pyruvic
acid to lactic acid.
Hormones:
Insulin, that regulates the
glucose utilization in the
body.
Contractile Proteins:
Actin & Myosin, that
change the shape to
produce contraction of
muscle fibres.
Storage Proteins:
Ovalbumin, that act as
food for embryo.
Transport Proteins:
Hemoglobin, that
transport Oxygen from
lungs to the rest of the
body.

7. Lactate dehydrogenase Human Insulin
Actin

8. Myosin
Hemoglobin molecule
Ovalbumin

9. Classification of Proteins
ON THE BASIS OF
SOLUBILITY
1. Water soluble: Albumin
2. Salt solution soluble:
Serum Globulin
3. Dilute acids & Alkalis
soluble: Glutenin
ON THE BASIS OF
NUTRITIONAL STATUS
1. Complete: Provide all
essential amino acids after
digestion.
2. Incomplete: Do not provide
all essential amino acids after
digestion.
ON THE BASIS OF
BIOLOGICAL
FUNCTION
1. Enzyme: Lactate
Dehydrogenase.
2. Hormones: Insulin.
3. Transport Proteins:
Hemoglobin
ON THE BASIS OF
COMPOSITION
1. Simple: One amino acid
present, Albumin.
2. Conjugated: Protein & Non-
protein part, Hemoglobin.
3. Derived: Partial hydrolysis
of proteins, Gelatin.
ON THE BASIS OF
SHAPE
1. Globular: Spherical in
shape, Hemoglobin.
2. Fibrous: Long fiber, thread
like, Keratin.

10. Zwitterion of amino acids & Isoelectric point
ALKALINE pHACIDIC pH

11. Structure of Proteins

12. Protein deficiency diseases

13. Protein energy malnutrition

14. Inborn errors of protein metabolism
1. Maple syrup Urine Disease

15. 2. Hartnup Disease

16. 3. Phenyl ketonuria

17. 4. Alkapton-uria

18. Identification test for proteins
1. BIURET TEST:
• Procedure- 3 ml sample+ 3 ml
of 5% Sodium Hydroxide + few
drops of 10% Copper Sulphate
solution.
• Observation- Violet colour
• Result/inference- This test is
used to detect peptide linkages,
hence violet colour indicates the
formation of 2 molecules of
urea.
2. NINHYDRIN TEST:
• Procedure- 1 ml sample+ 10 drops
of Ninhydrin solution.
• Observation- Blue colored
complex
• Result/inference- This test is used
to detect the free amino groups
present, hence blue colored complex
indicates that the ninhydrin
molecule gets reduced by the free
amino group.
3. MILLON’S TEST/ COLE TEST:
• Procedure- 1 ml sample+ 3-4
drops of Millon’s reagent+ heat for
10 min.+ cool+ 5 drops of Sodium
nitrite.
• Observation- Brick red color
• Result/inference- This test is used
to detect the presence of aromatic
amino acids, hence brick red color
indicates the presence of aromatic
amino acid e.g. Tyrosine.

19. 4. GLYOXYLLIC ACID/ HOPKINS
COLE TEST:
• Procedure- 5-6 drops of sample+ 2
ml of reagent+ Concentrated
Sulphuric acid.
• Observation- Violet color at the
junction.
• Result/inference- This test is used
to detect the presence of indole
ring, hence the indole ring reacts
with glyoxylic acid and gives violet
color at the junction e.g.
Tryptophan.
5. NITROPRUSSIDE TEST:
• Procedure- 1 ml of sample + 0.5
ml of sodium nitroprusside
solution+ 1 ml of Ammonia
Solution.
• Observation- Red color.
• Result/inference- This test is
used to detect the presence of
Sulphur containing amino acids,
hence in the presence of ammonia
solution, the Sulphur reacts with
nitroprusside to give red color.
6. SAKAGUCHI TEST:
• Procedure- 1 ml of sample + 1
ml of sodium hydroxide solution+
2-3 drops of Alpha-naphthol+ 4-5
drops of bromine water.
• Observation- Red color.
• Result/inference- This test is
used to detect the presence of
guanidine group, for e.g. in the
presence of guanidine group, the
arginine reacts with Alpha-
naphthol to give red color in the
presence of bromine water.

20. 7. SULPHUR TEST/ LEAD
SULPHATE TEST:
• Procedure- 3 ml of sample + 3 ml of
40% sodium hydroxide solution+ 2-3
drops of lead acetate solution.
• Observation- Black or brown colored
precipitate.
• Result/inference- This test is used to
detect the presence of Sulphur group in
amino acid, for e.g. Peptone gives this
test positive due to presence of
Sulphur group.
8. NEUMANN TEST:
• Procedure- 5 ml of sample + 0.5 ml
of 40% sodium hydroxide solution +
heat + cool + add concentrated
Nitric Acid + to the filtrate add 2-3
drops of Ammonium Molybdate.
• Observation- Canary yellow color
• Result/inference- This test is used
to detect the presence of phosphorus
group in amino acid, for e.g. Casein
gives this test positive due to
presence of Phosphorus group as
non-protein part.
9. XANTHOPROTEIC TEST:
• Procedure- 1 ml of sample +
1 ml concentrated Nitric
Acid + boil + Add Sodium
Hydroxide dropwise.
• Observation- Yellow color
to Orange color
• Result/inference- This test is
based on the nitration of
aromatic ring of aromatic
amino acids for e.g. Tyrosine.

21. General reactions of Amino acids

22. Transamination

23. Deamination

25. Decarboxylation

26. Urea cycle

27. Steps involved in protein synthesis

28. Disorders of protein metabolism
1. CYSTINURIA
***Apart from Cystinuria, other disorders are Alkaptonuria, Hypoproteinemia,
Necrobiosis and Allergies etc.***