Brief on Amino Acid

1. Ms. Shrutika Joshi
M.Pharm (Pharmaceutical Chemistry)
Asst. Professor
University Inst. of Pharmacy
Oriental University, Indore

2. C
An amino acid is an organic molecule that is made up of a
basic amino group (−NH2) an acidic carboxyl group (−COOH) and an
organic R group (side chain) that is unique to each aminoacid.
The term amino acid is short for α-amino carboxylicacid.
Amino acid are methane derivative.
All amino acid are chiral carbon except glycine.
NH2
R COOH
H
C
Glycine

3. Peptide bond formation:-
The amino acids are a result of protein hydrolysis.
C
H2N COOH
R
+
H2O
C
H
R
H2N C
H
N C
H
R
COOH
O
C COOH
R
H H H
H N
Peptide bond

4.  Aqueous solution amino acids exist in two forms the molecular
form and the zwitterions form in equilibrium with each other.
 All amino acids contain amine and carboxylic acid functional
groups they are amphiprotic.

5.  Experts classify amino acids based on a variety of features
including whether people can acquire them through diet.
 Accordingly scientists recognize three amino acid types:
1. Nonessential
2. Essential
3. Semi-essential
 The classification as essential or nonessential does not actually
reflect their importance as all 20 amino acids are necessary for
human health.

6. 1.Essential:- Eight of these amino acids are essential and cannot
be produced by the body. They are:
Leucine
Methionine
Isoleucine
Lysine
Threonine
Phenylalanine
Valine
Tryptophan

7. 2.Semi-essential:- Histidine is an amino acid that is categorized as
semi-essential since the human body doesn't always need it to
properly function therefore dietary sources of it are not always
essential.
3.Nonessential:-Nonessential amino acids are produced by the
human body. Nonessential amino acids include:-
Asparagine
Alanine
Arginine
Aspartic acid
Cysteine
Glutamic acid
Glutamine
Proline
Glycine
Tyrosine
Serine

8. Amino acids containing sulfur:-
Cysteine and Methionine
Neutral amino acids:-
Asparagine, Serine, Threonine, and Gluta
Acidic:-
Glutamic acid and Asparticacid
Basic:-
Arginine and Lysine
Aliphatic amino acids:-
Leucine, Isoleucine, Glycine, Valine, andAlanine
Aromatic amino acids:-
Phenylalanine, Tryptophan, Tyrosine andHistidine

9. Final amino acid classification is categorized by the side chain
structure that divides the list of 20 amino acids into four groups 1.
1.Non-polar:- Side chains having pure hydrocarbon alkyl or
aromatic groups are considered non-polar.
e.g.
Phenylalanine(Aromatic) Glycine V
aline Leucine
.

10. Alanine Isoleucine Proline
Methionine Tryptophan(Aromatic)

11. 2.Polar:- Side chain contains different polar groups like
amides, acids and alcohols.
e.g.
Tyrosine-(Aromatic) Serine Asparagine
Threonine Glutamine Cysteine

12. 3. Acidic and polar:- The side chain contains carboxylic acid.
(Negatively charged residues)
e.g.
Glutamic Acid AsparticAcid
4. Basic and polar:- Side chain consists of a carboxylic acid and
basic-polar. (Positively charged residues)
e.g.
Lysine Histidine Arginine

13. C
R COOH
NH2
H
Amino group
CarboxylicAcid
AminoAcid
Reactive group present in amino
acid that can give Several chemical
reaction

14. 1. SALT FORMATION WITH
ACID AND BASE
2. FORMATION OFPEPTIDE
BOND
1.FORMATION OF ESTER
2. FORMATION OFAMINO
ACYLCHLORIDE
3. DECARBOXYLATION
4. AMIDE FORMATION
Reaction of amino acid
REACTION DUE TO
COOH AND NH3 GROUP
REACTION DUE TO
COOH GROUP
REACTION DUE TO
NH3 GROP
1ACYLATION
2.BENZOYLATION
3.METHYLATION
4.REACTIONWITH
SANGERS REAGENT
5.REACTION WITH NH2
6.OXIDATIVE
DEAMINATION
7.RXN-FORMALDEHYDE
8.RXN-AROMATIC
ALDEHYD
9.NINHYDRIN REACTION
10.RXN-CO2
11.BIURET REACTION

15. GLYCOLYSIS
Glucose
Glucose -6-Phosphate
3-Phosphoglycerate
PEP
Pyruvate
Ribose -5-
Phosphate
Phosphoribosyl-
Pyrophosphate
Histidine
PPPPathway
Serine 0-acetyl Serine Cysteine
Valine
Ketoiso
Caproic acid
Leucine
Ketoisovoleric acid Transamination
Transamination
Alanine
Shikimic acid
Chorisimic acid
Prephenic
acid
Anthranilic
acid
Phenylalanine Tyrosine
Tryptophan
Erythose-4-phosphate
Glycine
Acetyle CoA

16. .
Acetyl CoA
Citrate
Oxalo acetate
Ketogluterate
Malate
TCA
Cycle
Glutamate
Proline
Glutamine
Ornithine
Citruline
Arginine
NH3
Hydroxy proline
Aspartate
NH3
NH3
Asparagine Diamino pimelate
Lysine
Homoserine
Crystathionine
Methionine
Threonine
Isoleucine

17. 1. Decarboxylation Reaction:-
Removal of carboxyl group of amino acid as carbon dioxide with
the formation of amine is called decarboxylation.
General reaction:-
 DPLP:-Decarboxylase pyridoxal phosphate.
 Biogenic amines

19. Decarboxylation
Histidine:-

20. 2.Transamination Reaction:-
Transamination involves the Transfer of alpha- amino group
from of alpha-amino acid to an alpha-keto acid to from new
amino acid and a new keto acid.
Transfer of amino group from an amino acid to the keto
group of a keto-acid.
The enzyme that catalyze these reaction are called
transaminases or aminotransferases.

21. All ransaminases require pyridoxal phosphate (PLP) as a
coenzyme.
Lever, Kidny, Heartand Brain-adequate amount of these
enzyme
Transaminase reaction take place in cytoplasm.

22. The transamination reaction results in the exchange of an amine
group on one amino acid with a ketone group on another amino
acid.
The most usual and major keto acid involved with transamination
reactions is alpha-ketoglutaric acid .It is intermediate in the citric
acid cycle.
e.g.
A specific example is the transamination of alanine to make
pyruvic acid and glutamic acid.

23. H 3 C C
H
C O H
N H 2 O
O O O
H2 H2
HO C C C C C OH
H3C C
O
O
C C
OH H
H H
2 2
C C C
HO
O NH2 O
Alpha-ketoglutaric acid
Transamination of alanine to make pyruvic acid and glutamic
acid
Glutamic acid
Alanine
C OH
Pyruvic acid
ALT

24. Transamination of Aspartate to make Oxaloacetate acid and glutamicacid
H2
C C
H
C OH
NH2 O
O O O O
O
H2 H2
HO C C C C C OH
O O
H H
2 2
C C C
O
OH
C
H
C
HO
O NH2
AST
Alpha-ketoglutaric acid Glutamic acid
HO C
Aspartate
H2
HO C C C C OH
Oxaloacetate

29. The urea cycle is the first metabolic pathway
to be elucidated.
The cycle is known as Krebs–Henseleit urea
cycle.
Ornithine is the first member of the reaction,
it is also called as Ornithine cycle.
Urea is synthesized in liver &transported to
kidneys for excretion in urine.

30. The two nitrogen atoms of urea are derived
from two different sources, one from
ammonia &the other directly from the a-
amino group of aspartic acid.
Carbon atom is supplied by CO2
Urea is the end product of protein metabolism
(amino acid metabolism).

31. Urea accounts for 80-90%of the nitrogen
containing substances excreted in urine.
Urea synthesis is a five-step cyclic process,
with five distinct enzymes.
The first two enzymes are present in
mitochondria while the rest are localized in
cytosol.

32. O

33. Carbamoyl phosphate synthase I (CPSI) of
mitochondria catalyses the condensation of
NH4
+ ions with CO2to form carbamoyl
phosphate.
Thisstep consumes two ATP&is irreversible.
It is a rate-limiting.

34. CPSI requires N-acetylglutamate for its
activity.
Carbamoyl phosphate synthase II (CPSII) -
involved in pyrimidine synthesis &it is present
in cytosol.
It accepts amino group from glutamine &does
not require N-acetylglutamate for its activity.

35. CO2+ NH3 + 2ATP Carbamoyl Phosphate
+ 2ADP + Pi
Carbamoyl phosphate
synthetase-I

36. CPS-I
Mitochondria
Uses NH3
Urea Cycle
Activated – NAG
CPS-II
Cytosol
Uses Glutamine
Pyrimidine
biosynthesis
Inhibited - CTP

37. The second reaction is also mitochondrial.
Citrulline is synthesized from carbamoyl
phosphate &ornithine by ornithine
transcarbamoylase.
Ornithine is regenerated &used in urea
cycle.

38. Ornithine &citrulline are basic amino acids.
(Never found in protein structure due to lack
of codons).
Citrulline is transported to cytosol by a
transporter system.
Citrulline is neither present in tissue proteins
nor in blood; but it is present in milk.

39. Ornithine + Carbamoyl phosphate Citrulline + Pi
Ornithine
Transcarbomylase

40. Citrulline condenses with aspartate to form
arginosuccinate by the enzyme
Arginosuccinate synthetase.
Second amino group of urea is incorporated.
It requires ATP
,it is cleaved to AMP &PPi
2High energy bonds are required.
Immediately broken down to inorganic
phosphate (Pi).

41. The enzyme Argininosuccinase or
argininosuccinate lyase cleaves
arginosuccinate to arginine &fumarate (an
intermediate in TCA cycle)
Fumarate provides connecting link with TCA
cycle or gluconeogenesis.

42. The fumarate is converted to oxaloacetate
via fumarase &MDH &transaminated to
aspartate.
Aspartate is regenerated in this reaction.
Fumarate Malate
Fumarase MDH
Oxaloacetate Aspartate
Aminotransferase
NAD+ NADH+H+

43. Arginase is the 5thand final enzyme that
cleaves arginine to yield urea & ornithine.
Ornithine is regenerated, enters
mitochondria for its reuse in the urea cycle.
Arginase is activated by Co2+& Mn2+
Ornithine &lysine compete with arginine
(competitive inhibition).

44. Arginase is mostly found in the liver, while the
rest of the enzymes (four) of urea cycle are
also present in other tissues.
Arginine synthesis may occur to varying
degrees in many tissues.
But only the liver can ultimately produce urea.

46. Thank you