AMINO ACIDS

1. Chemistry of Natural Products
AMINO ACIDS
Presented to: Dr. Syeda Abida Ejaz
Presented by : Aamna Khatoon
M.Phil pharmaceutical Chemistry
1st Semester Spring 2021-2023
.

2. Amino Acids
An amino acid is bi functional organic molecule that contains both a
carboxyl group –COOH as well a an amine group -NH2
Amino acids are derived from proteins have the amino group on the
alpha (α) carbon i.e; the carbon atom next to the carboxyl group
Amino Acids are building blocks of proteins
There are 300 amino acids which occur in nature , among these 20
are known as standard amino acids that most commonly occur in
proteins
 These 20 amino acids are encoded by universal genetic code. These
are known as Standard Amino acids
 Non Standard amino acids are those amino acids which don’t have
a genetic code, they are formed by post translational modifications

3. Amino Acids differ in nature of R- group Attached to α carbon atom.
The nature of R- group determines the properties of amino acids and
proteins
Central carbon is called as α Carbon as both functional groups are
attached to this Carbon

4. Amino Acids
Proteins are formed by joining the carboxyl group of one amino acid
to the α-amino group of another amino acid
The bond formed between two amino acids with the elimination of
water is called as peptide linkage

5. Sr.
no
Name Abbreviation Structure
1 Glycine
Simplest amino acid, having no
asymmetric carbon , and sweet taste
Gly:G
2 Alanine Ala:A
3 Serine
It has OH group that is involved in
hydrogen bonding with phosphates and
carbohydrates
Ser:S

6. Sr.
no
Name Abbreviation Structure
4 Threonine
It has OH group that is involved in hydrogen bonding
with phosphates and carbohydrates
Thr:T
5 Valine
It has branched side chain
Val:V
6 Leucine
It has branched side chain
Leu:L

7. Sr.
no
Name Abbreviation Structure
7 Isoleucine
Having branched side chains
Ile:I
8 Cysteine
Sulphonyl group in cysteine is an
important component of the active site
of many enzymes, also form disulfide
linkage in proteins
Cys:C
9 Methionine
It is also Sulphur containing amino acid
Met: M

8. Sr.
no
Name Abbreviation Structure
10 Phenylalanine Phe: F
11 Tyrosine
It is named so as it was first isolated
from cheese
Tyr:Y
12 Tryptophan Trp:W

9. Sr.
no
Name Abbreviation Structure
13 Aspartic acid
At pH 7 it has net negative charge
Asp:D
14 Asparagine
It is named so as it was first isolated
from asparagus
Asn:N
15 Glutamic Acid
At pH 7 it has net negative charge
Glu:E

10. Sr.
no
Name Abbreviation Structure
16 Glutamine
It is amide of glutamic acid
Gln:Q
17 Lysine
It has positive charge at pH 7, it can be
post translationally hydroxylated to
form hydroxylysine
Lys: K
18 Arginine
At pH 7 it has net positive charge
Arg:R

11. Sr.
no
Name Abbreviation Structure
19 Histidine
It has positive charge on pH 7
His:H
20 Proline
it can aslo be post translationally
hydroxylated to form 4-hydroxyproline
Pro:P

12. Non Standard Amino Acids
Sr.no. Name Biological role
1 Citrulline These three amino acid occur in liver, where they take part in urea
cycle
2 Ornithine
3 Argininosuccinic Acid
4 Pantothenic acid It is widely distributed vitamin and is a part of CoA-SH
5 Β- Alanine It is part of molecule of vitamin known as pantothenic acid
6 ϒ- Amino Butyric Acid GABA , it is a neurotransmitter
7 7- deoxy phenyl alanine DOPA, formed by metabolism of phenylalanine and tyrosine
Used in the treatment of Parkinson disease
8 Homocycteine Structural component of proteins
9 Iodinated Amino Acids Tyrosine is iodinated in thyroid gland and they act as thyroid
hormone.

13. Classification of Amino Acids
Amino Acids are classified into different ways
On the basis of Polarity
On the basis of structure
On the basis of Nutritional Requirement
On the basis of Metabolic fate

14. Classification of Amino Acids – Polarity
Sr.no Class Examples
1 Non polar Amino Acids Alanine, Valine, Leucine, Isoleucine,
Phenyl alanine, glycine, tryptophan,
methionine and proline
2 Polar Amino Acids - Neutral Serine, threonine, tyrosine, cysteine,
glutamine, asparagine
3 Polar Amino Acids – Positively
Charged
Lysine, arginine, histidine
4 Polar Amino Acids –
Negatively Charged
Aspartic acid , Glutamic acid

15. Classification of Amino Acids – Structure
Sr no. Class Example
1 Aliphatic Side Chain Glycine, alanine, valine, leucine, isoleucine
2 Aromatic side Chain Phenyl alanine, tryptophan, tyrosine
3 Hydroxyl-containing side
chain
Serine, threonine
4 Sulfur- containing side chains Cysteine, methionine
5 Basic Side chains Lysine, Arginine ,Histidine
6 Acidic side chains Glutamate, aspartate
7 Imino Acids Proline

16. Classification of Amino Acids – Nutritional
Requirements
Sr. No
Class Properties Example
1 Essential Amino Acids Human Body cannot synthesize
them , required to be obtained
from environment in food
Valine, Isoleucine, leucine, lysine,
methionine, phenylalanine, threonine,
tryptophan
2 Conditionally Essential Amino
Acids
Normally body can synthesize
them , but in certain conditions
their supplementation is
required to full fill body
requirements
Like in growing children,
pregnant women
Arginine, histidine, Tyrosine
3 Non Essential Amino Acids Body can synthesize these
amino acids by itself
Glycine, alanine, serine, glutamine,
aspartate, cysteine, glutamate, asparagine,
proline

17. Classification of Amino Acids – Metabolic Fate

18. • The amino group and carboxylic acid group present in amino acids allow them to have
amphiprotic property
• Carboxylic acid group donates its proton to Amino group and it form Zwitter ion
• At physiological pH of 7.4 Zwitter ion is formed
Amino acids may be positively charged, negatively charged or neutral depending upon the pH of
medium and nature of R group
Properties of Amino acids –Zwitter Ion

19. Properties of Amino acids –Stereoisomerism
• Amino acids exhibit stereoisomerism, they exist as enantiomers , L and D form
• They are optically active as all of them have a chiral carbon
• L- amino acids occur naturally in proteins, D amino acids are formed by
posttranslational modification
• D- serine act as neurotransmitter in brain
• Some D-Amino acids are also present is bacterial cell.

20. Sources of Amino Acids-Protein
Sr.no Source Scientific name Constituents
1 Quinoa Chenopodium quinoa All 9 essential amino acids , rich in lysine
2 Eggs - All essential amino acids
3 Turkey Meleagris gallopavo High amounts of typtophan
4 Cottage Cheese - 100g fullfill 25% of daily requirement
5 Mushrooms - 17 amino acids , rich in lysine
6 Fish - All essential amino acids and omega-3-
fatty acids
7 Legumes and
beans
- All essential amino acids , 25-30% of their
protein is rich in lysine

21. Amino Acids-As Drug
Sr.no Name Use
1 Arginine An amino acid commonly found as a component of total parenteral nutrition
2 Aminocaproic Acid An antifibrinolytic agent used to induce clotting postoperatively.
3 L-Glutamine An amino acid commonly found as a component of total parenteral nutrition
4 Histidine An amino acid commonly found as a component of total parenteral nutrition
5 Ademetheonine S-Adenosylmethionine (SAMe) is used as a drug in Europe for the treatment
of depression, liver disorders, fibromyalgia, and osteoarthritis. It has also been
introduced into the United States market
6 Phenyl alanine An amino acid commonly found as a component of total parenteral nutrition
7 Aspartic Acid An amino acid commonly found as a component of total parenteral nutrition
8 Serine An amino acid commonly found as a component of total parenteral nutrition
9 Methionine An amino acid commonly found as a component of total parenteral nutrition
10 Tyrosine An amino acid commonly found as a component of total parenteral nutrition

22. Extraction of free amino acids from tomato leaves
R. CARPENA-RUIZ,1988
• Plant :Lycopersicon esculentum
• Collection : leaves were taken from between 1st and 2nd Flowering tops,
central vein was removed and leaves were cut into small pieces
• Preservation : emersed in 50ml of absolute ethanol at -18°C, then they
were frozen in liquid Nitrogen, freeze Dried at -56°C for 24 hours.
Thereafter, the samples were ground for 2 min in absolute ethanol in an
ice-bath, using a Polytron. The extracts were stored at -18°C
• Extraction : The solid residues were then extracted with 80mL of 80%
(v/v) ethanol either by shaking or by Soxhlet assembly at 40°C and 100°C
for 3, 6 and 9 hours under reduced pressure.
• Amino acid determination: was done using ion exchange
chromatography in a Kontron 500 autoanalyzer (Lee, 1974). Lithium
citrate buffers of 2.75, 3.15 and 3.60 were used and the temperature during
analysis changed from 37 to 68°C over the time period of 110min.

23. Extraction of free amino acids from tomato leaves
R. CARPENA-RUIZ,1988
Result :Overall amino acid content of extracts was decreased by 20% after extraction at 100°C
The most concentrated extracts were those obtained by Soxhlet extraction of freeze-dried samples,
The most efficient extraction was obtained with. 1.0 g of leaves for 80 mL of extractant
Sample after 9 hour contain maximum concentration of amino acids

24. THANK YOU