This document discusses amino acids, which are the building blocks of proteins. It defines amino acids as having both a carboxyl group and an amine group. There are 20 standard amino acids that commonly occur in proteins. Amino acids differ in their R groups, which determine the properties of amino acids and proteins. Proteins are formed by linking amino acids through peptide bonds formed by the elimination of water. The document also classifies amino acids based on polarity, structure, nutritional requirements, and metabolic fate. It discusses amino acid sources from foods like quinoa and eggs. Some amino acids are also used as drugs to treat conditions like depression and liver disorders. The document concludes with describing an extraction method for free amino acids from tomato

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