amino acid is building block of amino acid.

1. AMINO ACIDS
Building blocks of protein
Mrs. Praveen Garg
VITS College, Satna

2. INTRODUCTION
 Amino acids are organic compounds that combine to form
proteins.
 Amino acids and proteins are the building blocks of life.
 When proteins are digested or broken down, amino acids are
left.
 Amino acids contain amine and carboxyl functional groups,
along with a side chain specific to each amino acid.
 The key elements of an amino acid are carbon, hydrogen,
oxygen, and nitrogen, although other elements are found in
the side chains of certain amino acids.
 Amino acids can also be used as a source of energy by the
body.

3.  The human body uses amino acids to make proteins to help the
body.
• Break down food
• Grow
• Repair body tissue
• Perform many other body functions

4. • Arginine - Arg – R
• Lysine - Lys – K
• Aspartic acid - Asp – D
• Glutamic acid - Glu – E
• Glutamine - Gln – Q
• Asparagine - Asn – N
• Histidine - His – H
• Serine - Ser – S
• Threonine - Thr – T
• Cysteine - Cys - C
• Tryptophan - Trp – W
• Tyrosine - Tyr – Y
• Methionine - Met – M
• Alanine - Ala – A
• Isoleucine - Ile – I
• Leucine - Leu – L
• Phenylalanine - Phe – F
• Valine - Val – V
• Proline - Pro – P
• Glycine - Gly - G
TYPES OF AMINO ACIDS
The 20 most common amino acids in proteins are listed with their three
letter and one-letter codes:

5. ESSENTIAL AMINO ACIDS
• Essential amino acids
cannot be made by the body.
As a result, they must come
from food.
Example:
• Histidine, isoleucine,
leucine, lysine, methionine,
phenylalanine,
threonine, tryptophan, and
valine.
NONESSENTIAL AMINO ACIDS
• Nonessential means that
our bodies produce an
amino acid, even if we do
not get it from the food we
eat.
Example:
• Alanine, arginine,
asparagine, aspartic acid,
cysteine, glutamic acid,
glutamine, glycine, proline,
serine, and tyrosine.
CLASSIFICATION
Amino acids are classified into two groups:

6.  They can be classified according to the core structural functional
groups' locations as alpha-(α-), beta-(β-), gamma-(γ-) or delta-(δ-
) amino acids.
 Other categories relate to polarity, pH level, and side chain group
type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur,
etc.).

7. Classification Based on Polarity
Non polar amino acids:
• They have equal number
of amino and carboxilic
group.
• These are hydrophobic
and no charge on the R
group.
• Example: alanine, valine,
leucine, isoleucine,
phenyl alanine, glycine,
tryptophen, methionine
and proline.

8. Polar amino acid with no charge:
• They do not have any charge on R group.
• They help in participate in hydrogen bonding of protein structure.
• Example: serine, threonine, tyrosine, cysteine, glutamine,
aspargine.

9. Polar amino acid with positive charge:
• They have more amino groups as compared to carboxyl groups
making it basic.
• Example: Lysine, Arginine, Histidine

10. Polar amino acid with negative charge:
• They have more carboxilic group than amino group making
them acidic.
• Example: Aspartic acid, Glutamic acid

11.  Acidic amino acids: These contain one amino and two
carboxilc group.
Example: Aspartic acid, glutamic acid
 Basic amino acids: These contain an additional basic
such as amino group, guanidine, imidazole.
Example: Lysine, Arginine, Histidine
 Neutral amino acids: These contain one amino and one
carboxilic group.
Example: Glycine, Alanine, etc.
Classification Based on Acid/Base

12. ZWITTER ION
• A zwitterion, also called an inner salt, is a molecule that contains
an equal number of positively and negatively charged functional
groups.
• The example of zwitter ion is amino acid that contain -COOH
and –NH2 group in same molecule.
• In aqueous solution, -COOH group loses a proton (H+) to form a
carboxylate (-COO-) ion while –NH2 group gains a proton to
form –NH3 ion, thus they exist as a dipolar ion at pH 7. Such a
ion is called zwitter ion.

13. Acidic solution Neutral solution
Zwitter ion
Alkaline solution
• Amino acids are amphoteric molecule, they can donate or
accept protons and act like as acidic and basic.

14. PROPERTY OF AMINO ACIDS
Physical Properties:
• Amino acids are colorless, crystalline solid.
• They are soluble in water, slightly soluble in alcohol and
dissolve with difficulty in methanol, ethanol, and propanol.
• R-group of amino acids and pH of the solvent play important
role in solubility.
• All amino acids have a high melting point greater than 200o
• All amino acids (except glycine) are optically active.
• Amino acids can connect with a peptide bond involving their
amino and carboxylate groups.
• A covalent bond formed between the alpha-amino group of
one amino acid and an alpha-carboxyl group of other forming
-CO-NH-linkage.

15. Chemical property
1. Decarboxylation: In this process, amino acids produce
amines.
Example: Histidine Histamine + CO2
Tyrosine Tyramine + CO2
Glutamic acid Gamma aminobutyric acid + CO2
Tryptophen Tryptamine + CO2
,
Due to –COOH group

16. 2. Reaction with ammonia: The carboxyl group of
dicarboxilic amino acids react with NH3 to form amide.
• Aspartic acids + NH3 Asparagine
• Glutamic acids + NH3 Glutamine
3. Salt formation: Amino acids form salts (-COONa) with bases
and form esters (-COOR) with alcohols.

17.  Due to – NH2 group
1. Reaction with Sanger reagent: 1-Fluoro-2,4-dinitrobenzene
(commonly called Sanger's reagent, dinitrofluorobenzene, DNFB
or FDNB) is a chemical that reacts with the N-terminal amino
acid of polypeptides and produce yellow color derivatives 2,4
dinitrobenzene (DNB).

18. 2. Edmann reaction:
An uncharged peptide is reacted with phenylisothiocyanate
(PITC) at the amino terminus under mildly alkaline conditions
to give a phenylthiocarbamoyl derivative (PTC-peptide).

19. 3. Nin hydrin reaction:
• Ninhydrin reacts with the α-amino group of primary amino
acids producing 'Ruhemann's purple'. The chromophore formed is
the same for all primary amino acids.

20. Functions of Amino acids
• In particular, 20 amino acids are crucial for life as they form
peptides and proteins and are known to be the building blocks
for all living things.
• The linear sequence of amino acid residues in a polypeptide
chain determines the 3D- configuration of a protein, and the
structure of a protein determines its function.
• Amino acids are essential for the health of the human body.
 They largely promote the production of hormone.
 Structure of muscles
 Human nervous system’s healthy functioning
 The health of vital organs.
 Normal cellular structure

21. • The amino acids are used by various tissues to synthesize
proteins and to produce nitrogen-containing compounds (e.g.,
purines, heme, creatine, epinephrine), or they are oxidized to
produce energy.
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