Amino Acid : Introduction Classification Reaction Physical property Function

1. St. Thomas College Bhilai
Seminar On:
Amino Acid
Paper 4: (Biomolecules)
Guided By:
Mrs. Ujjwala Supe
Session- 2020-2021
Submitted By:
Anjali Bisen
M.Sc 1st Semester
Biotechnology 1

2. ❖Amino acid are organic compounds
containing amino group,a carboxyl group
and a side chain that is specific to each
amino acid .
❖An amino acid in which amino group is on
the carbon adjacent to the carboxyl group.
❖Amino acid are building blocks of protein .
❖There are 300 amino acid occur in nature
only 20 of them occur in protein.
❖The key elements of amino acids are
C,N,O,H.
INTRODUCTION
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Fig:1

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GENERAL STRUCTURE OF AMINO ACID :-
The amino acid are termed as a- amino acid ,if both the carboxyl
and amino group are attached to the same carbon atom .
Fig:2

4. CLASSIFICATION OF AMINO ACID :-
There are different ways of classifying the amino acid :-
1.Based on structure
2.Based on the polarity
3.Nutritional classification
4.Based on metabolic fate
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5. BASED ON STRUCTURE :-
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Fig:3 Fig:4

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Fig:6 Fig:7

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Fig:8

8. BASED ON POLARITY :-
NON POLAR ,ALIPHATIC AMINO ACID :-the R group in this class of amino acid are nonpolar and
hydrophobic .
Glycine , valine , leucine , isoleucine , methionine , proline .
AROMATIC AMINO ACID :-are with their aromatic side chains,are relatively non polar .
Phenylalanine , tyrosine , tryptophan .
POLAR, UNCHARGED AMINO ACID :-the R group of these amino acid are more soluble in water than those
of non polar amino acid .
Serine , threonine , cysteine , asparagine , glutamine .
ACIDIC AMINO ACID :-R group acidic or negatively charged.
Glutamic acid , aspartic acid .
BASIC AMINO ACID:-R group is basic or positively charged.
Lysine , arginine , histidine 8

9. 9
Fig:9

10. Based on metabolic fate :-
Glucogenic amino acid: These aa Ketogenic amino acid:These aa
serve as precursors gluconeogenesis breakdown to form ketone bodies .
for glucose formation.
Both glucogenic & ketogenic:These aa breakdown to form precursors for both ketone bodies &
glucose .
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Fig:10

11. Nutritional classification :-
1. Essential amino acid- nine amino acid cannot be synthesized in body & therefore must be present in
the diet.
2. Non essential amino acid-these amino acid can be synthesized in the body.
3. Conditionally.
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Fig:11

12. Amino acid as ampholytes :-
★Amino acid contain both acidic group (-COOH) & basic (-NH2) group.
★They can donate or accept a proton & hence known as ampholytes.
★In strongly acidic pH amino acid is positively charged .
★In strongly alkaline pH amino acid is negatively charged.
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Fig:12

13. Isoelectric pH
★Isoelectric pH may be defined as pH at which molecule exist as a zwitterion or dipolar ion & carries
no net charge.
★Molecule is electrically neutral at isoelectric pH.
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Fig:13

14. Stereochemistry of amino acids
★All amino acids are optically active (except glycine)
★All amino acid have one asymmetrical carbon or chiral carbon ,to which four ,groups are
attached ( carboxyl group,amino group,hydrogen group , rgroup )
★The mirror image of a molecule of amino acid are non superimposable to each other.
★Amino acid do not have plane of symmetry .
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Fig:14

15. stereochemistry
★All amino acid rotate the plane of polarized light .
★These are non superimposable mirror image of each other and known as
enantiomer of each other.
★If the carboxyl group at the top,the D form refers to the isomer having -
NH2 at the right; the L form refers to the amino acid having -NH2 at the
left.
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16. Physical properties of amino acid:-
●Solubility: most of the amino acid are soluble in water & insoluble in organic
solvent.
●Melting point: amino acid generally melt at higher temperature , often above
200c .
●Taste: amino acid may be sweet (Gly,Ala,Val) ,tasteless (Arg,Ile)
●Monosodium glutamate (MSG ; ajinomoto) is used as flavouring agent in food
industry. 16

17. Reaction of amino acid:-
0 amino acid form salts with base
(COONa) & esters (COOR)with alcohols.
0 the carboxylic group of dicarboxylic
Amino Acids reacts with NH3 to form amide.
➔Aspartic acid + NH3
asparagine
O amino acid undergo decarboxylation
to produce corresponding amine. 17
Fig:15
Fig:16

18. Function of amino acid:-
1.Provide monomer units from which the long polypeptide chain of
protein are synthesized.
2.Amino acid also useful as durg .
3.GABA (neurotransmitter) is synthesized from glutamic acid.
4.Nitric oxide a smooth muscle relaxant is synthesized from Arginine.
5.Short polymer of aa called polypeptide perform prominent role in
neuroendocrine system as hormone and hormone releasing factor ,
neurotransmitter.
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19. Reference:-
❏ Lehninger Principles of Biochemistry; David L.Nelson , Michael M.Cox; 5th
Edition ; W.H. Freeman & Company ;New York
P.g. no.-72-81.
❏ Biochemistry ,U.Satyanarayana
❏ www.slideshare.net/mobile/namarta28/chemistry-of-amino-acids-13558789
❏ https://www.slideshare.net/mobile/mizan00/amino-acid-ppt
❏ https://www.biologydiscussion.com/amino-acids/amino-acids-concept-
classification-and-reactions/16937
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