Classification of Amino Acids, List of essential and non-essential amino acids, Essential Amino Acids, Chemistry of Amino Acids, 1) Zwitterions (physical properties), Detecting Amino acids, Introduction of Polypeptide, Polypeptide Chain.

1. PRESENTED BY
MS. MONIKA P. MASKE
ASSISTANT PROFESSOR
M. PHARM
(PHARMACEUTICAL CHEMISTRY)

2. Proteins, Amino Acids and
Polypeptide

3. Introduction
 Proteins are naturally occurring polymers made up of amino acids linked together by
peptide bonds (-CO-NH) having high molecular weight biomolecules, found in all living
systems.
- Minimum mol. wt. : 5000-8000
- No. of amino acids : > 100
 Proteins are made up of 20 -amino acids.

4. Functions of Proteins
 Proteins which catalyse biochemical reactions called as enzymes.
 Proteins responsible for transportation of metabolites or gases (gases,CO2) called as
transport proteins.
 It control metabolic pathways called regulatory proteins (insulin).
 It responsible to protect from infection & other toxic sub. Called as antibodies or
defence proteins.
 It required to give strength to cells or tissues are called as Structural proteins.
 It required to carry out mechanical work called as muscle proteins.

5. Classification of Proteins

6. Depending upon the chemical nature, proteins are broadly classified as :
1) Simple proteins :
Simple protein yields only amino acids on hydrolysis.
(a) Protamine’s: These are very basic proteins of low mol. wt. (3000-10000).
(b) Histones : These are basic proteins with higher mol. wt. than protamine's.
(c) Albumins & globulins : These are globular proteins.
(d) Epidermal proteins : These are proteins of skin, hair, nails.
(e) Sclero proteins : These are connective tissue proteins such as collagen.

7. 2) Conjugated proteins :
These contain simple protein molecules united with nonprotein
group and on hydrolysis they yield other non-proteineous substances in addition to amino acids.
1) Lipoproteins: These are composed of lipids and proteins.
Ex: Lipoprotein of egg yolk, milk, cell membrane & lipoprotein of bloods.
1. Very high density lipoproteins.
2. High density lipoproteins.
3. Low density lipoproteins.
4. Very low density lipoproteins

8. 2) Nucleoproteins: These are the conjugated proteins having proteins and nucleicacid.
Ex: Ribosome, Nucleoproteins.
3) Metalloproteins: These proteins are conjugated and proteins.
Ex: Hemoglobin – with iron.
4) Phosphoproteins: Contain phosphorus radical as prosthetic group.
Ex: Caseinogens (milk), Ovovitellin (egg yolk).
5) Flavoproteins: Contain riboflavin as a prosthetic group.
Ex: Flavoproteins of liver & kidney.

9. 3) Derived proteins:
These are intermediate hydrolysis products, which are formed by the action of physical
(heat), chemical or enzymatic agents on natural proteins.
 Primary derivatives: Ex; Proteans, Metaproteins, Coagulated proteins.
 Secondary derivatives: Ex; Proteoses, Peptones, Peptides.

11. Qualitative Tests For Proteins
1. Heat test – Protein solution is heated in boiling water bath proteins get coagulated and
loose biological activity.
2. Test with trichloroacetic acid (TCA) – TCA + protein solution results ppt.
3. Biuret test – Biuret reagent consists of copper sulphate in alkaline medium its results
in violet colour. Show the presence of proteins estimation.
4. Hydrolysis test – this test carry out with ninhydrin and Biuret test results gives free
amino acids like HCl.
5. Xanthoproteic test – Nitration(con. Nitric acid) of aromatic amino acids of proteins give
yellow colour.

12. 6. Millons test – Phenolic grp. Of tyrosine of proteins + mercuric sulphate in the presence
of sodium nitrite and sulphuric acid gives red colour.
7. Precipitation test – Proteins are ppt. by using different agents such as
- Salts: ammonium sulphate, sod. Chloride
- Organic solvents: Acetone, alcohol
- Heavy metals: copper, mercury, sod. Tungstate
- Acids: acetic acid, HCl

13. Biological Value of Proteins
 Proteins give amino proteins on hydrolysis during digestion and amino acid are
absorbed in the blood.
 Amino acids are required for cell to synthesize proteins.
 Production of proteins required for synthesis of metabolites.
 Ex. Histamine is formed from histidine.

14. Protein Deficiency Diseases
Protein deficiency in early childhood is regarded as disease.
 Kwashiorkor – The qualitative & quantitative deficiency of protein’s in chlidern results in
the disease kwashiorkor.
- It appears in children between age 1-4 years.
- symptoms are retarded growth, edema, alteration in skin, hair pigmentation.
- factors responsible for large family size, poor mental health, premature breast feeding.
- Milk, eggs, soya-beans helps to curing disease.

15.  Marasmus – The protein and other nutritional deficiencies in infants below one year is called
marasmus.
- Protein and energy deficiency disease is also known as marasmic kwashiorkor.
- it occurs more in poor people.
- Symptoms same as kwashiorkor.
- it occurs due to early stoppage of breast feeding.
- it overcome with diet rich in calories, proteins, nutrition.

16.  Nutritional oedema – Long continued deprivation of proteins results in nutritional edema.
- It occurs in famine areas.
- In adult is very rare.
- Symptoms are loss of wt. , anaemia, delay in healing ,in capacity in work.
- overcome by used of soyabean, milk, eggs.

18. Introduction

19. Classification of Amino Acids

24. Essential Amino Acids

25. Chemistry of Amino Acids

27. 1) Zwitterions (physical properties)

28. 2) Solubility: Amino acid soluble in water solubility depends upon R-grp i.e polarity of amino
acid. Non polar amino acid highly soluble in organic solvents like ether, chloroform.
3) Acid-Base behaviour: Amino acids contain acidic carboxyl grp. and basic amino grp.
Hence, amino acids are called as amphoteric molecules or ampholytes.

29. Detecting Amino acids

30. Polypeptide
 These are short polymers formed from the linking in defined order no acids.
peptides < 50 amino acids
 Peptide are classified according to no. of amino acids.
1) Polypeptides
2) Oligopeptides

31. Polypeptides

32. Polypeptide Chain

33. Thank You