Introduction of amino acid Common structure of amino acid History Classification of amino acid basis on R-group Non polar aliphatic R group Aromatic R group Uncharged polar R group Positive Charge R group Negative charge R group Properties of amino acids Conclusions References

1. CLASSIFICATION OF AMINO ACID
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. Synopsis
 Introduction of amino acid
 Common structure of amino acid
 History
 Classification of amino acid basis on R-group
 Non polar aliphatic R group
 Aromatic R group
 Uncharged polar R group
 Positive Charge R group
 Negative charge R group
 Properties of amino acids
 Conclusions
 References

3. Introduction
 Amino acid is a biomolecule.
 Proteins are polymers of amino acids.
 Twenty different amino acids are commonly found in proteins.
 Amino acid composed of an amino group, a carboxyl group, a hydrogen
atom and an R group, all bonded to a carbon atom, α carbon.

4. Common Structure of Amino Acids
 Amino acid are compound containing carbon, hydrogen, oxygen, nitrogen
and attached with carbon by the hydrogen bond .
 The α carbon is also called chiral center.
 All 20 of the common amino acids are α amino acids.
 Amino acids are differ from each other in their side chains or R groups,.

5. History
 The first to be discovered was asparagines’, in 1806.
 The last of the 20 to be found, threonine, was not identified until 1938.

6. Amino Acids Can Be Classified by R Group
 The topic can be simplified by grouping the amino acids
into five main classes based on the properties of their R
groups,
The five group are-
 Non polar, aliphatic (7)
 Aromatic (3)
 Polar, uncharged (5)
 Positively charged (3)
 Negatively charged (2)

7. Nonpolar, Aliphatic R Groups
 The R groups in this class of amino acids are non polar and
hydrophobic.
 The side chains of alanine, valine, leucine, and isoleucine
tend to cluster together within proteins.
 Glycine, has the simplest structure.
 Methionine, one of the two sulfur-containing amino acids.
 Proline has an aliphatic side chain with a different cyclic
structure.

9. Nonpolar, Aromatic R Groups
 Phenylalanine, tyrosine, and tryptophan, with their aromatic side
chains, are relatively non polar (hydrophobic).
 All can participate in hydrophobic interactions.
 Tyrosine and tryptophan are significantly more polar than
phenylalanine, because of the tyrosine hydroxyl group and the nitrogen
of the tryptophan indole ring.

11. Polar, Uncharged R Groups
 The R groups of these amino acids are more soluble in water, or more
hydrophilic.
 This class of amino acids includes serine, threonine, cysteine,
asparagine, and glutamine.
 The polarity of serine and threonine is contributed by their hydroxyl
groups; that of cysteine by its sulfhydryl group;
 Asparagine and glutamine by their amide groups.

13. Positively Charged R Groups
 The most hydrophilic R groups are those that are either positively or
negatively charged.
 lysine, which has a second primary amino group at the position on its
aliphatic chain.
 Arginine, which has a positively charged guanidino group; and
histidine, which has an imidazole group.

15. Negatively Charged R Groups
• The two amino acids having R groups with a net negative charge at pH
7.0are aspartate and glutamate

17. Property of amino acid

18. Some important points
 The one – letter code war devised by
Margarent Oakley Dayhoff (1925-1983).
 It was designed to be easily
memorized and understanding .

19. Conclusions
 Amino acid are bio molecules.
 Amino acid is compound containing ,carbon, oxygen, nitrogen, and
hydrogen atom.
 Protein is a polymer of amino acid.
 Amino acid classify mainly in five group basis on the R groups.
 Non polar aliphatic R group
 Non polar aromatic R group
 Polar uncharged R group
 Positive charge R group
 Negative charge R group

20. References
 Michael M.cox & David L. Nelson - Lehninger principle of
biochemistry , 5th edition
 DM Vasudevan, Sreekumari S - Biochemistry , 6th edition
 Robert K.MURRAY, David A. BENDER – Illustrated biochemistry , 29th
edition
 Pranav Kumar , Usha Mina- life sciences, 3rd edition