SlideShare une entreprise Scribd logo
1  sur  20
Télécharger pour lire hors ligne
Dr. Mausumi Adhya
Associate Professor
Supreme Knowledge Foundation, Hooghly
Amino acid: Amino acid-definition, classification, function, properties
Amino acids
Amine group –NH2 Acid group -COOH
H
N
H
C
H
R
C
OH
O
H
N
+
H
C
H
R
C
O
--
O
H
amino acid
(free)
amino acid
(zwitter ion)
Although over 200 different amino acids occur in nature, only 20 of these form backbone
of proteins.
 L–α–amino acids
 α-amino group, a α-carboxylic acid group
 Building block of peptides and proteins.
 Source of sulfur: sulfur containing amino acids cysteine, methionine.
 Source of energy: Amino acids converts to glucose by gluconeogenesis.
 Precursor of biological molecules: tyrosine is the precursor of hormone thyroxine and
skin pigment melanin, tryptophan is the precursor of vitamin 𝑩𝟑 (niacin).
Functions amino acids in human body
Structure of L–α–amino acids
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
C
C
H
COOH
NH2
CH2
Glycine
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
H2
CH3
Isoleucine
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
C
H
COOH
NH2
CH2
CH2
CO
N
H2
Glutamine
Phenylalanine
C
H
COOH
NH2
CH2
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Glycine
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
CH2
COOH
HOOC
C
H
CH2
CH2
C
H3
HOOC
C
H
CH2
CO
N
H2
C
H
CH2
CH2
CO
N
H2
C
H
CH2
C
H
CH2
O
H
C
H
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
H
COOH
NH2
CH2
CH2
S
C
H3
Methionine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
2
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
H
COOH
NH2
CH2
CH2
S
C
H3
Methionine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
COOH
CH2
O
H
Serine
C
H
COOH
NH2
CH2
CO
N
H2
C
H
COOH
NH2
CH2
CH2
CO
N
H2
C
H
COOH
NH2
CH2
C
H
COOH
NH2
CH2
O
H
C
H
COOH
NH2
CH2
CH
N
H
C
H
COOH
CH
CH
CH
CH
N
H
NH2
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
H
COOH
NH
CH2
CH2
S
C
H3
Methionine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
COOH
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
COOH
C
H3
Glycine
Alanine
Valine
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
COOH
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
COOH
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H
COOH
NH2
CH2
Glycine
Alanine
Valine
Leucine
COOH
CH3
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
C
H
COOH
NH2
CH2
CH2
CO
N
H2
Glutamine
COOH
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Glycine
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
COOH
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
2
C
H3
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
H
COOH
NH2
CH2
CH2
S
C
H3
Methionine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
COOH
NH2
CH2
O
H
Serine
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
COOH
NH2
CH
C
H3
OH
Threonine
NH2
Glutamine
Phenylalanine
C
H
COOH
NH2
CH2
Tyrosine
C
H
COOH
NH2
CH2
O
H
Tryptophan
C
H
COOH
NH2
CH2
CH
N
H
C
H
COOH
NH2
CH2
CH2
CH2
CH2
N
H2
Lysine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH
CH
Histidine
Structure of amino acids
C
H
NH2
CH2
CH2
S
C
H3
Methionine
C
H
COOH
NH2
CH2
O
H
Serine
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
COOH
NH2
CH
C
H3
OH
Threonine
N
H2
Structure of amino acids
C
H
NH2
CH2
O
H
Serine
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
COOH
NH2
CH
C
H3
OH
Threonine
C
H
COOH
NH2
CH2
CH2
CH2
CH2
N
H2
Lysine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH
CH
Histidine
Structure of amino acids
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
NH2
CH
C
H3
Threonine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH
CH
Histidin
Structure of amino acids
C
H
COOH
NH2
CH2
CH2
S
C
H3
Methionine
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
COOH
NH2
CH2
O
H
Serine
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
COOH
NH2
CH
C
H3
OH
Threonine
Tyrosine
C
H
COOH
NH2
CH2
O
H
Tryptophan
C
H
COOH
NH2
CH2
CH
N
H
C
H
COOH
NH2
CH2
CH2
CH2
CH2
N
H2
Lysine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH
CH
Histidine
Structure of amino acids
ine
ucine
hionine
ne
ne
teine
eonine
NH2
2
2
2
Glutamine
Phenylalanine
C
H
COOH
NH2
CH2
Tyrosine
C
H
COOH
NH2
CH2
O
H
Tryptophan
C
H
COOH
NH2
CH2
CH
N
H
C
H
COOH
NH2
CH2
CH2
CH2
CH2
N
H2
Lysine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH Histidine
amino acids
C
H
COOH
NH2
H
C
H
COOH
NH2
C
H3
C
H
COOH
NH2
CH
C
H3
C
H3
C
H
COOH
NH2
CH2
CH
C
H3
C
H3
Glycine
Alanine
Valine
Leucine
C
H
COOH
NH2
CH
CH2
C
H3
CH3
Isoleucine
C
H
COOH
CH2
CH2
S
C
H3
C
COOH
H
NH
CH2
C
H2
C
H2
Proline
C
H
COOH
NH2
CH2
COOH
Aspartic ac
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic a
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
C
H
COOH
NH2
CH2
CH2
CO
N
H2
Glutamine
Phenylalan
C
H
COOH
NH2
CH2
Tyrosine
C
H
COOH
NH2
CH2
O
H
C
H
COOH
CH2
CH
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
C
H
COOH
NH2
CH2
CH2
CO
N
H2
Glutamine
Phenylalanine
C
H
COOH
NH2
CH2
Tyrosine
C
H
COOH
NH2
CH2
O
H
Tryptophan
C
H
COOH
NH2
CH2
CH
N
H
C
H
COOH
CH2
CH2
CH2
CH2
NH2
Serine
C
H
COOH
NH2
CH2
S
H
Cysteine
C
H
COOH
NH2
CH
C
H3
OH
Threonine
C
H
NH2
CH2
CH2
CH2
CH2
N
H2
Lysine
C
H
COOH
NH2
CH2
CH2
CH2
NH
CH
N
H2
NH
Arginine
C
H
COOH
NH2
CH2
C
HC
N NH
CH
Histidine
Structure of amino acids
COOH
NH2
COOH
NH2
COOH
NH2
COOH
NH2
Glycine
Alanine
Valine
Leucine
COOH
NH2 Isoleucine
COOH
C
H
COOH
NH2
CH2
COOH
Aspartic acid
HOOC
C
H
COOH
NH2
CH2
CH2
C
H3
Glutamic acid
HOOC
C
H
COOH
NH2
CH2
CO
N
H2
Asparagine
C
H
COOH
NH2
CH2
CH2
CO
N
H2
Glutamine
Phenylalanine
C
H
COOH
NH2
CH2
C
H
COOH
CH
Structure of L–α–amino acids
Classification of amino acids
 based on the structure of the side chain 𝐑
 based on their acid and base nature
 based on the polarity of the side chain 𝐑
 based on their nutritional value
 based on their metabolic fate
H
N
H
C
H
R
C
OH
O
amino acid
(free)
 Phenylalanine
Based on the structure of the side chain 𝑹
 Aliphatic amino acids: having aliphatic groups in their side chains
 Glycine
 Alanine
 Valine
 Leucine
 Methionine
 Aspartic acid
 Asparagine
 Glutamic acid
 Isoleucine
 Serine
 Threonine
 Cysteine
 Glutamine
 Arginine
 Proline
 Lysine
 Aromatic amino acids: having aromatic groups in their side chains.
 Histidine
 Tryptophan
 Tyrosine
Based on their acid and base nature
 Acidic amino acids: Side chain 𝐑 contains a carboxylic acid functional group.
 Glutamic acid  Aspartic acid
 Basic amino acids: Side chain 𝐑 contains an amine functional group.
 Arginine  Histidine.
 Lysine
 Neutral amino acids: Dont have any amino group or carboxylic acid group in side chain R.
 Glycine
 Alanine
 Valine
 Leucine
 Methionine
 Asparagine
 Phenylalanine
 Tyrosine
 Isoleucine
 Serine
 Threonine
 Cysteine
 Glutamine
 Proline
 Tryptophan
Based on the polarity of the side chain 𝐑
 Polar amino acids: Various functional groups like acid, amide, alcohol, amine in side chain R
 Serine
 Threonine
 Tyrosine
 Asparagines
 Cysteine
 Glutamine
 Aspartic acid
 Glutamic acid
 Histidine
 Lysine
 Arginine
 Non-polar amino acids: Pure hydrocarbon groups (aliphatic and aromatic) in side chain R
 Glycine
 Alanine
 Valine
 Leucine
 Isoleucine
 Phenylalanine
 Tryptophan
 Methionine
 Proline
Based On Their Nutritional Value
 Essential amino acids: Can not be synthesized in human body and must be taken in diet.
 Valine
 Leucine
*Arginine and histidine are essential in children, but not in adults.
 Isoleucine
 Phenylalanine
 Methionine
 Tryptophan
 Threonine
 Histidine
 Lysine
 Arginine
 Non-essential amino acids: Can be synthesized in human body and hence they are non-
essential in the diet.
Alanine
asparagine
 Aspartic Acid
 Glutamic Acid
 Glutamine
 Glycine
 Proline
 Serine
 Cysteine
 Tyrosine
Based On Their Metabolic Fate
 Glucogenic amino acids: Used for glucose synthesis only.
 Glycine
 Alanine
 Methionine
 Aspartic acid
 Cysteine
 Histidine
 Glutamine
 Arginine
 Proline
 Valine
 Serine
 Asparagine
 Glutamic acid
 Ketogenic amino acids: Used for ketone body synthesis only.
 Lysine  Leucine
 Ketogenic and glucogenic amino acids: Used for both
ketone body synthesis and glucose synthesis.
 Tryptophan  Tyrosine  Threonine
 Isoleucine
 Phenylalanine
General properties of α-amino acids
1. Optical activity
2. Acid-Base properties of amino acids
3. Amphoteric properties of amino acids
4. Zwitterions form
5. Isoelectric point pI
6. Buffering capacity of amino acids
7. Physical properties of amino acids
:
Buffering capacity of amino acids
Physical properties of amino acids
 Amino acids are mainly water soluble.
 They are soluble in polar solvents and not soluble in non-polar solvents.
 They have high melting point.
 A buffer is a solution which resists changes in 𝒑𝑯 when limited amount of acid or base is
added to it.
 A buffer is a mixture of a weak acid and its conjugate base or a weak base and its
conjugate acid.
Buffering capacity of amino acids
 An amino acid has both an acidic group (carboxyl ) and a basic group (amine). Carboxyl
group acts as conjugate acid (proton donor) and amino group acts as proton
acceptor. Therefore together carboxyl group and amino group resists change in pH when
small amount of acid or base is added.
 For example glycine, glutamic acid and histidine use for preparation of buffer.
Optical activity of amino acids
 The ability of a substance to rotate plane-polarized monochromatic light is called
optical activity.
 The compound having carbon atom with four different groups is generally optically
active.
 All amino acids except glycine contain a tetrahedral carbon attached to four different
groups (-COOH, -NH2, -R and –H).
 In glycine, the tetrahedral carbon is attached to three different groups (-COOH, -NH2,
and –H).
 Therefore all amino acids except glycine is optically active.
Acid-Base properties of amino acids
 All amino acids contain at least two ionizable groups; an amine group (-NH2) and a
carboxylic acid group (-CO2H).
 Some amino acids contain an additional acidic (-CO2H) or basic group (-NH2) in their side
chain, which are responsible for acid-base behaviour of amino acids.
 Aspartic acid, glutamic acid are acidic amino acids.
 Arginine, histidine, lysine are basic amino acids.
 Other 15 amino acids are neutral.
Zwitterions form of amino acids
 A zwitterion is a neutral molecule with a positive and a negative electrical charge. All
neutral amino acids are present in zwitterions form at physiological 𝐩𝐇 (around 7.4).
H
N
H
C
H
R
C
OH
O
H
N
+
H
C
H
R
C
O
--
O
H
amino acid
(free)
amino acid
(zwitter ion)
 But acidic and basic amino acids form zwitter ions at different pH.
R C COOH
NH3
H
R C COO
--
NH3
H
R C COO
--
NH2
H
pKa1 pKa2
H
+
HO
--
+ +
at acidic pH (cation) at neutral pH (zwitterion) at basic pH (anion)
Isoelectric point (𝐩𝐈) of amino acids
 All amino acids have specific pH in which they form zwitter ion.
 It is that 𝐩𝐇 at which net electrical charge of an amino acid is equal to zero ,and
thus at this 𝐩𝐇 the amino acid can not move in an electric field.
 𝐩𝐈 value varies from one amino acid to other. It is the average of two 𝒑𝑲𝒂 values.
𝐩𝐈 =
𝟏
𝟐
(𝒑𝑲𝒂𝟏 + 𝒑𝑲𝒂𝟐)
R C COOH
NH3
H
R C COO
--
NH3
H
R C COO
--
NH2
H
pKa1 pKa2
H
+
HO
--
+ +
at acidic pH (cation) at neutral pH (zwitterion) at basic pH (anion)
Amphoteric properties
An amphoteric species is a molecule or ion that can
react as an acid as well as a base. Due to presence of
ionizable amine and carboxylic acid groups, amino
acids can act sometimes as acids and sometimes as
bases depending on the 𝐩𝐇 of their media and
isoelectric point.
H+ donate: Acid
H+ accept: Base
OH- donate: base
OH- accept: acid
Electrons donate: Base
Electrons accept: acid
Amino Acids.pdf

Contenu connexe

Tendances

Tendances (20)

Amino Acids.pptx
Amino Acids.pptxAmino Acids.pptx
Amino Acids.pptx
 
Amino acids
Amino acidsAmino acids
Amino acids
 
Amino acids and proteins
Amino acids and proteinsAmino acids and proteins
Amino acids and proteins
 
Amino acids structure
Amino acids structureAmino acids structure
Amino acids structure
 
4.3 proteins
4.3   proteins4.3   proteins
4.3 proteins
 
14 proteins
14 proteins14 proteins
14 proteins
 
Four levels of protein structure
Four levels of protein structureFour levels of protein structure
Four levels of protein structure
 
Chemistry of protein
Chemistry of protein Chemistry of protein
Chemistry of protein
 
Amino acids and proteins
Amino acids and proteinsAmino acids and proteins
Amino acids and proteins
 
Chemistry of amino acids
Chemistry of amino acidsChemistry of amino acids
Chemistry of amino acids
 
Protein Chemistry
Protein ChemistryProtein Chemistry
Protein Chemistry
 
Amino acids
Amino acidsAmino acids
Amino acids
 
Metabolism of essential and non essential amino acids 20
Metabolism of essential and non  essential amino acids 20Metabolism of essential and non  essential amino acids 20
Metabolism of essential and non essential amino acids 20
 
Classification of protein
Classification of proteinClassification of protein
Classification of protein
 
INTRODUCTION TO METABOLISM OF PROTEIN AND AMINO ACIDS
INTRODUCTION TO METABOLISM OF PROTEIN AND AMINO ACIDS INTRODUCTION TO METABOLISM OF PROTEIN AND AMINO ACIDS
INTRODUCTION TO METABOLISM OF PROTEIN AND AMINO ACIDS
 
Amino acid
Amino acidAmino acid
Amino acid
 
Chemistry of amino acids&proteins
Chemistry of amino acids&proteinsChemistry of amino acids&proteins
Chemistry of amino acids&proteins
 
Protein structure & function
Protein structure & functionProtein structure & function
Protein structure & function
 
Proteins
ProteinsProteins
Proteins
 
Proteins
ProteinsProteins
Proteins
 

Similaire à Amino Acids.pdf

Chemistry of amino acids
Chemistry of amino acidsChemistry of amino acids
Chemistry of amino acidsRamesh Gupta
 
aminoacidbysridarshinichandra1-1-160424175247.pdf
aminoacidbysridarshinichandra1-1-160424175247.pdfaminoacidbysridarshinichandra1-1-160424175247.pdf
aminoacidbysridarshinichandra1-1-160424175247.pdfMariamMansour32
 
Amino acid
Amino acidAmino acid
Amino acidNimmiRoy
 
Amino acids structure classification & function by KK Sahu sir
Amino acids structure classification & function by KK Sahu sirAmino acids structure classification & function by KK Sahu sir
Amino acids structure classification & function by KK Sahu sirKAUSHAL SAHU
 
chemistryofaminoacidsproteins-140307154509-phpapp02.pdf
chemistryofaminoacidsproteins-140307154509-phpapp02.pdfchemistryofaminoacidsproteins-140307154509-phpapp02.pdf
chemistryofaminoacidsproteins-140307154509-phpapp02.pdfanju468752
 
6. AMINO ACIDS.pptx
6. AMINO ACIDS.pptx6. AMINO ACIDS.pptx
6. AMINO ACIDS.pptxABDULRAUF411
 
Lec.1 aminoacid.chem
Lec.1 aminoacid.chemLec.1 aminoacid.chem
Lec.1 aminoacid.chemShamim Akram
 
Amino Acids for Dentistry
Amino Acids  for DentistryAmino Acids  for Dentistry
Amino Acids for DentistryAyman Abdo
 
Amino acids (1)
Amino acids (1)Amino acids (1)
Amino acids (1)kumar
 
Amino acids and protein
Amino acids and proteinAmino acids and protein
Amino acids and proteinAbhinav yadav
 
Amino Acids and Proteins.ppt
Amino Acids and Proteins.pptAmino Acids and Proteins.ppt
Amino Acids and Proteins.pptMohammed539308
 
Amino Acids- Structure and Clasisfications
Amino Acids- Structure and ClasisficationsAmino Acids- Structure and Clasisfications
Amino Acids- Structure and ClasisficationsSurajVasave3
 

Similaire à Amino Acids.pdf (20)

Amino Acids.docx
Amino Acids.docxAmino Acids.docx
Amino Acids.docx
 
C-A&P 01 amino acids classification
C-A&P 01 amino acids classificationC-A&P 01 amino acids classification
C-A&P 01 amino acids classification
 
Chemistry of amino acids
Chemistry of amino acidsChemistry of amino acids
Chemistry of amino acids
 
aminoacidbysridarshinichandra1-1-160424175247.pdf
aminoacidbysridarshinichandra1-1-160424175247.pdfaminoacidbysridarshinichandra1-1-160424175247.pdf
aminoacidbysridarshinichandra1-1-160424175247.pdf
 
Amino acid
Amino acidAmino acid
Amino acid
 
Amino acid
Amino acid Amino acid
Amino acid
 
AMINO ACIDS.pdf
AMINO ACIDS.pdfAMINO ACIDS.pdf
AMINO ACIDS.pdf
 
Proteins
ProteinsProteins
Proteins
 
Amino acids structure classification & function by KK Sahu sir
Amino acids structure classification & function by KK Sahu sirAmino acids structure classification & function by KK Sahu sir
Amino acids structure classification & function by KK Sahu sir
 
chemistryofaminoacidsproteins-140307154509-phpapp02.pdf
chemistryofaminoacidsproteins-140307154509-phpapp02.pdfchemistryofaminoacidsproteins-140307154509-phpapp02.pdf
chemistryofaminoacidsproteins-140307154509-phpapp02.pdf
 
6. AMINO ACIDS.pptx
6. AMINO ACIDS.pptx6. AMINO ACIDS.pptx
6. AMINO ACIDS.pptx
 
Amino acids
Amino acidsAmino acids
Amino acids
 
Lec.1 a.a.chem
Lec.1 a.a.chemLec.1 a.a.chem
Lec.1 a.a.chem
 
Lec.1 aminoacid.chem
Lec.1 aminoacid.chemLec.1 aminoacid.chem
Lec.1 aminoacid.chem
 
Amino Acids for Dentistry
Amino Acids  for DentistryAmino Acids  for Dentistry
Amino Acids for Dentistry
 
Amino acids (1)
Amino acids (1)Amino acids (1)
Amino acids (1)
 
Amino acids and protein
Amino acids and proteinAmino acids and protein
Amino acids and protein
 
Amino Acids and Proteins.ppt
Amino Acids and Proteins.pptAmino Acids and Proteins.ppt
Amino Acids and Proteins.ppt
 
Amino Acids- Structure and Clasisfications
Amino Acids- Structure and ClasisficationsAmino Acids- Structure and Clasisfications
Amino Acids- Structure and Clasisfications
 
Protein chemistry
Protein chemistry Protein chemistry
Protein chemistry
 

Plus de Mausumi Adhya

Determination of partition coefficient of acetic acid between water and n-bu...
Determination of partition coefficient  of acetic acid between water and n-bu...Determination of partition coefficient  of acetic acid between water and n-bu...
Determination of partition coefficient of acetic acid between water and n-bu...Mausumi Adhya
 
Estimation of iron in Mohr salt .pdf
Estimation of iron in Mohr salt .pdfEstimation of iron in Mohr salt .pdf
Estimation of iron in Mohr salt .pdfMausumi Adhya
 
Determination of hardness in water .pdf
Determination of hardness in water .pdfDetermination of hardness in water .pdf
Determination of hardness in water .pdfMausumi Adhya
 
Determination of dissolved oxygen.pdf
Determination of dissolved oxygen.pdfDetermination of dissolved oxygen.pdf
Determination of dissolved oxygen.pdfMausumi Adhya
 
Estimation of chloride ion in water
Estimation of chloride ion in waterEstimation of chloride ion in water
Estimation of chloride ion in waterMausumi Adhya
 
Alkalinity of given water sample.pdf
Alkalinity of given water sample.pdfAlkalinity of given water sample.pdf
Alkalinity of given water sample.pdfMausumi Adhya
 

Plus de Mausumi Adhya (7)

Determination of partition coefficient of acetic acid between water and n-bu...
Determination of partition coefficient  of acetic acid between water and n-bu...Determination of partition coefficient  of acetic acid between water and n-bu...
Determination of partition coefficient of acetic acid between water and n-bu...
 
Estimation of iron in Mohr salt .pdf
Estimation of iron in Mohr salt .pdfEstimation of iron in Mohr salt .pdf
Estimation of iron in Mohr salt .pdf
 
Determination of hardness in water .pdf
Determination of hardness in water .pdfDetermination of hardness in water .pdf
Determination of hardness in water .pdf
 
Determination of dissolved oxygen.pdf
Determination of dissolved oxygen.pdfDetermination of dissolved oxygen.pdf
Determination of dissolved oxygen.pdf
 
Estimation of chloride ion in water
Estimation of chloride ion in waterEstimation of chloride ion in water
Estimation of chloride ion in water
 
Alkalinity of given water sample.pdf
Alkalinity of given water sample.pdfAlkalinity of given water sample.pdf
Alkalinity of given water sample.pdf
 
Protein.pdf
Protein.pdfProtein.pdf
Protein.pdf
 

Dernier

Bureau of Indian Standards Specification of Shampoo.pptx
Bureau of Indian Standards Specification of Shampoo.pptxBureau of Indian Standards Specification of Shampoo.pptx
Bureau of Indian Standards Specification of Shampoo.pptxkastureyashashree
 
Principles & Formulation of Hair Care Products
Principles & Formulation of Hair Care  ProductsPrinciples & Formulation of Hair Care  Products
Principles & Formulation of Hair Care Productspurwaborkar@gmail.com
 
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptx
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptxQ3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptx
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptxArdeniel
 
Pests of ragi_Identification, Binomics_Dr.UPR
Pests of ragi_Identification, Binomics_Dr.UPRPests of ragi_Identification, Binomics_Dr.UPR
Pests of ragi_Identification, Binomics_Dr.UPRPirithiRaju
 
Pests of Redgram_Identification, Binomics_Dr.UPR
Pests of Redgram_Identification, Binomics_Dr.UPRPests of Redgram_Identification, Binomics_Dr.UPR
Pests of Redgram_Identification, Binomics_Dr.UPRPirithiRaju
 
Substances in Common Use for Shahu College Screening Test
Substances in Common Use for Shahu College Screening TestSubstances in Common Use for Shahu College Screening Test
Substances in Common Use for Shahu College Screening TestAkashDTejwani
 
Lehninger_Chapter 17_Fatty acid Oxid.ppt
Lehninger_Chapter 17_Fatty acid Oxid.pptLehninger_Chapter 17_Fatty acid Oxid.ppt
Lehninger_Chapter 17_Fatty acid Oxid.pptSachin Teotia
 
Gene transfer in plants agrobacterium.pdf
Gene transfer in plants agrobacterium.pdfGene transfer in plants agrobacterium.pdf
Gene transfer in plants agrobacterium.pdfNetHelix
 
soft skills question paper set for bba ca
soft skills question paper set for bba casoft skills question paper set for bba ca
soft skills question paper set for bba caohsadfeeling
 
Physics Serway Jewett 6th edition for Scientists and Engineers
Physics Serway Jewett 6th edition for Scientists and EngineersPhysics Serway Jewett 6th edition for Scientists and Engineers
Physics Serway Jewett 6th edition for Scientists and EngineersAndreaLucarelli
 
Role of Herbs in Cosmetics in Cosmetic Science.
Role of Herbs in Cosmetics in Cosmetic Science.Role of Herbs in Cosmetics in Cosmetic Science.
Role of Herbs in Cosmetics in Cosmetic Science.ShwetaHattimare
 
Identification of Superclusters and Their Properties in the Sloan Digital Sky...
Identification of Superclusters and Their Properties in the Sloan Digital Sky...Identification of Superclusters and Their Properties in the Sloan Digital Sky...
Identification of Superclusters and Their Properties in the Sloan Digital Sky...Sérgio Sacani
 
RCPE terms and cycles scenarios as of March 2024
RCPE terms and cycles scenarios as of March 2024RCPE terms and cycles scenarios as of March 2024
RCPE terms and cycles scenarios as of March 2024suelcarter1
 
KeyBio pipeline for bioinformatics and data science
KeyBio pipeline for bioinformatics and data scienceKeyBio pipeline for bioinformatics and data science
KeyBio pipeline for bioinformatics and data scienceLayne Sadler
 
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...Sérgio Sacani
 
MARKER ASSISTED SELECTION IN CROP IMPROVEMENT
MARKER ASSISTED SELECTION IN CROP IMPROVEMENTMARKER ASSISTED SELECTION IN CROP IMPROVEMENT
MARKER ASSISTED SELECTION IN CROP IMPROVEMENTjipexe1248
 
Applied Biochemistry feedback_M Ahwad 2023.docx
Applied Biochemistry feedback_M Ahwad 2023.docxApplied Biochemistry feedback_M Ahwad 2023.docx
Applied Biochemistry feedback_M Ahwad 2023.docxmarwaahmad357
 
geometric quantization on coadjoint orbits
geometric quantization on coadjoint orbitsgeometric quantization on coadjoint orbits
geometric quantization on coadjoint orbitsHassan Jolany
 
Controlling Parameters of Carbonate platform Environment
Controlling Parameters of Carbonate platform EnvironmentControlling Parameters of Carbonate platform Environment
Controlling Parameters of Carbonate platform EnvironmentRahulVishwakarma71547
 

Dernier (20)

Bureau of Indian Standards Specification of Shampoo.pptx
Bureau of Indian Standards Specification of Shampoo.pptxBureau of Indian Standards Specification of Shampoo.pptx
Bureau of Indian Standards Specification of Shampoo.pptx
 
Principles & Formulation of Hair Care Products
Principles & Formulation of Hair Care  ProductsPrinciples & Formulation of Hair Care  Products
Principles & Formulation of Hair Care Products
 
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptx
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptxQ3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptx
Q3W4part1-SSSSSSSSSSSSSSSSSSSSSSSSCI.pptx
 
Pests of ragi_Identification, Binomics_Dr.UPR
Pests of ragi_Identification, Binomics_Dr.UPRPests of ragi_Identification, Binomics_Dr.UPR
Pests of ragi_Identification, Binomics_Dr.UPR
 
Pests of Redgram_Identification, Binomics_Dr.UPR
Pests of Redgram_Identification, Binomics_Dr.UPRPests of Redgram_Identification, Binomics_Dr.UPR
Pests of Redgram_Identification, Binomics_Dr.UPR
 
Substances in Common Use for Shahu College Screening Test
Substances in Common Use for Shahu College Screening TestSubstances in Common Use for Shahu College Screening Test
Substances in Common Use for Shahu College Screening Test
 
Lehninger_Chapter 17_Fatty acid Oxid.ppt
Lehninger_Chapter 17_Fatty acid Oxid.pptLehninger_Chapter 17_Fatty acid Oxid.ppt
Lehninger_Chapter 17_Fatty acid Oxid.ppt
 
Gene transfer in plants agrobacterium.pdf
Gene transfer in plants agrobacterium.pdfGene transfer in plants agrobacterium.pdf
Gene transfer in plants agrobacterium.pdf
 
soft skills question paper set for bba ca
soft skills question paper set for bba casoft skills question paper set for bba ca
soft skills question paper set for bba ca
 
Physics Serway Jewett 6th edition for Scientists and Engineers
Physics Serway Jewett 6th edition for Scientists and EngineersPhysics Serway Jewett 6th edition for Scientists and Engineers
Physics Serway Jewett 6th edition for Scientists and Engineers
 
Role of Herbs in Cosmetics in Cosmetic Science.
Role of Herbs in Cosmetics in Cosmetic Science.Role of Herbs in Cosmetics in Cosmetic Science.
Role of Herbs in Cosmetics in Cosmetic Science.
 
Identification of Superclusters and Their Properties in the Sloan Digital Sky...
Identification of Superclusters and Their Properties in the Sloan Digital Sky...Identification of Superclusters and Their Properties in the Sloan Digital Sky...
Identification of Superclusters and Their Properties in the Sloan Digital Sky...
 
RCPE terms and cycles scenarios as of March 2024
RCPE terms and cycles scenarios as of March 2024RCPE terms and cycles scenarios as of March 2024
RCPE terms and cycles scenarios as of March 2024
 
KeyBio pipeline for bioinformatics and data science
KeyBio pipeline for bioinformatics and data scienceKeyBio pipeline for bioinformatics and data science
KeyBio pipeline for bioinformatics and data science
 
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...
Digitized Continuous Magnetic Recordings for the August/September 1859 Storms...
 
MARKER ASSISTED SELECTION IN CROP IMPROVEMENT
MARKER ASSISTED SELECTION IN CROP IMPROVEMENTMARKER ASSISTED SELECTION IN CROP IMPROVEMENT
MARKER ASSISTED SELECTION IN CROP IMPROVEMENT
 
Cheminformatics tools and chemistry data underpinning mass spectrometry analy...
Cheminformatics tools and chemistry data underpinning mass spectrometry analy...Cheminformatics tools and chemistry data underpinning mass spectrometry analy...
Cheminformatics tools and chemistry data underpinning mass spectrometry analy...
 
Applied Biochemistry feedback_M Ahwad 2023.docx
Applied Biochemistry feedback_M Ahwad 2023.docxApplied Biochemistry feedback_M Ahwad 2023.docx
Applied Biochemistry feedback_M Ahwad 2023.docx
 
geometric quantization on coadjoint orbits
geometric quantization on coadjoint orbitsgeometric quantization on coadjoint orbits
geometric quantization on coadjoint orbits
 
Controlling Parameters of Carbonate platform Environment
Controlling Parameters of Carbonate platform EnvironmentControlling Parameters of Carbonate platform Environment
Controlling Parameters of Carbonate platform Environment
 

Amino Acids.pdf

  • 1. Dr. Mausumi Adhya Associate Professor Supreme Knowledge Foundation, Hooghly Amino acid: Amino acid-definition, classification, function, properties
  • 2. Amino acids Amine group –NH2 Acid group -COOH H N H C H R C OH O H N + H C H R C O -- O H amino acid (free) amino acid (zwitter ion) Although over 200 different amino acids occur in nature, only 20 of these form backbone of proteins.  L–α–amino acids  α-amino group, a α-carboxylic acid group
  • 3.  Building block of peptides and proteins.  Source of sulfur: sulfur containing amino acids cysteine, methionine.  Source of energy: Amino acids converts to glucose by gluconeogenesis.  Precursor of biological molecules: tyrosine is the precursor of hormone thyroxine and skin pigment melanin, tryptophan is the precursor of vitamin 𝑩𝟑 (niacin). Functions amino acids in human body
  • 4. Structure of L–α–amino acids C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C C C H COOH NH2 CH2 Glycine Alanine Valine Leucine C H COOH NH2 CH H2 CH3 Isoleucine C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine C H COOH NH2 CH2 CH2 CO N H2 Glutamine Phenylalanine C H COOH NH2 CH2 C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Glycine Alanine Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C COOH H NH CH2 C H2 C H2 Proline C H CH2 COOH HOOC C H CH2 CH2 C H3 HOOC C H CH2 CO N H2 C H CH2 CH2 CO N H2 C H CH2 C H CH2 O H C H NH2 C H3 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Alanine Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C H COOH NH2 CH2 CH2 S C H3 Methionine C COOH H NH CH2 C H2 C H2 Proline 2 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C H COOH NH2 CH2 CH2 S C H3 Methionine C COOH H NH CH2 C H2 C H2 Proline C H COOH CH2 O H Serine C H COOH NH2 CH2 CO N H2 C H COOH NH2 CH2 CH2 CO N H2 C H COOH NH2 CH2 C H COOH NH2 CH2 O H C H COOH NH2 CH2 CH N H C H COOH CH CH CH CH N H NH2 C H COOH NH2 C H3 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Alanine Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C H COOH NH CH2 CH2 S C H3 Methionine C COOH H NH CH2 C H2 C H2 Proline C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC COOH C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C H3 C H3 COOH C H3 Glycine Alanine Valine C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine COOH C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine COOH C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C H COOH NH2 CH2 Glycine Alanine Valine Leucine COOH CH3 C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine C H COOH NH2 CH2 CH2 CO N H2 Glutamine COOH C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Glycine Alanine Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine COOH C COOH H NH CH2 C H2 C H2 Proline
  • 5. 2 C H3 C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C H COOH NH2 CH2 CH2 S C H3 Methionine C COOH H NH CH2 C H2 C H2 Proline C H COOH NH2 CH2 O H Serine C H COOH NH2 CH2 S H Cysteine C H COOH NH2 CH C H3 OH Threonine NH2 Glutamine Phenylalanine C H COOH NH2 CH2 Tyrosine C H COOH NH2 CH2 O H Tryptophan C H COOH NH2 CH2 CH N H C H COOH NH2 CH2 CH2 CH2 CH2 N H2 Lysine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH CH Histidine Structure of amino acids C H NH2 CH2 CH2 S C H3 Methionine C H COOH NH2 CH2 O H Serine C H COOH NH2 CH2 S H Cysteine C H COOH NH2 CH C H3 OH Threonine N H2 Structure of amino acids C H NH2 CH2 O H Serine C H COOH NH2 CH2 S H Cysteine C H COOH NH2 CH C H3 OH Threonine C H COOH NH2 CH2 CH2 CH2 CH2 N H2 Lysine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH CH Histidine Structure of amino acids C H COOH NH2 CH2 S H Cysteine C H NH2 CH C H3 Threonine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH CH Histidin Structure of amino acids C H COOH NH2 CH2 CH2 S C H3 Methionine C COOH H NH CH2 C H2 C H2 Proline C H COOH NH2 CH2 O H Serine C H COOH NH2 CH2 S H Cysteine C H COOH NH2 CH C H3 OH Threonine Tyrosine C H COOH NH2 CH2 O H Tryptophan C H COOH NH2 CH2 CH N H C H COOH NH2 CH2 CH2 CH2 CH2 N H2 Lysine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH CH Histidine Structure of amino acids ine ucine hionine ne ne teine eonine NH2 2 2 2 Glutamine Phenylalanine C H COOH NH2 CH2 Tyrosine C H COOH NH2 CH2 O H Tryptophan C H COOH NH2 CH2 CH N H C H COOH NH2 CH2 CH2 CH2 CH2 N H2 Lysine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH Histidine amino acids C H COOH NH2 H C H COOH NH2 C H3 C H COOH NH2 CH C H3 C H3 C H COOH NH2 CH2 CH C H3 C H3 Glycine Alanine Valine Leucine C H COOH NH2 CH CH2 C H3 CH3 Isoleucine C H COOH CH2 CH2 S C H3 C COOH H NH CH2 C H2 C H2 Proline C H COOH NH2 CH2 COOH Aspartic ac HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic a HOOC C H COOH NH2 CH2 CO N H2 Asparagine C H COOH NH2 CH2 CH2 CO N H2 Glutamine Phenylalan C H COOH NH2 CH2 Tyrosine C H COOH NH2 CH2 O H C H COOH CH2 CH C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine C H COOH NH2 CH2 CH2 CO N H2 Glutamine Phenylalanine C H COOH NH2 CH2 Tyrosine C H COOH NH2 CH2 O H Tryptophan C H COOH NH2 CH2 CH N H C H COOH CH2 CH2 CH2 CH2 NH2 Serine C H COOH NH2 CH2 S H Cysteine C H COOH NH2 CH C H3 OH Threonine C H NH2 CH2 CH2 CH2 CH2 N H2 Lysine C H COOH NH2 CH2 CH2 CH2 NH CH N H2 NH Arginine C H COOH NH2 CH2 C HC N NH CH Histidine Structure of amino acids COOH NH2 COOH NH2 COOH NH2 COOH NH2 Glycine Alanine Valine Leucine COOH NH2 Isoleucine COOH C H COOH NH2 CH2 COOH Aspartic acid HOOC C H COOH NH2 CH2 CH2 C H3 Glutamic acid HOOC C H COOH NH2 CH2 CO N H2 Asparagine C H COOH NH2 CH2 CH2 CO N H2 Glutamine Phenylalanine C H COOH NH2 CH2 C H COOH CH Structure of L–α–amino acids
  • 6. Classification of amino acids  based on the structure of the side chain 𝐑  based on their acid and base nature  based on the polarity of the side chain 𝐑  based on their nutritional value  based on their metabolic fate H N H C H R C OH O amino acid (free)
  • 7.  Phenylalanine Based on the structure of the side chain 𝑹  Aliphatic amino acids: having aliphatic groups in their side chains  Glycine  Alanine  Valine  Leucine  Methionine  Aspartic acid  Asparagine  Glutamic acid  Isoleucine  Serine  Threonine  Cysteine  Glutamine  Arginine  Proline  Lysine  Aromatic amino acids: having aromatic groups in their side chains.  Histidine  Tryptophan  Tyrosine
  • 8. Based on their acid and base nature  Acidic amino acids: Side chain 𝐑 contains a carboxylic acid functional group.  Glutamic acid  Aspartic acid  Basic amino acids: Side chain 𝐑 contains an amine functional group.  Arginine  Histidine.  Lysine  Neutral amino acids: Dont have any amino group or carboxylic acid group in side chain R.  Glycine  Alanine  Valine  Leucine  Methionine  Asparagine  Phenylalanine  Tyrosine  Isoleucine  Serine  Threonine  Cysteine  Glutamine  Proline  Tryptophan
  • 9. Based on the polarity of the side chain 𝐑  Polar amino acids: Various functional groups like acid, amide, alcohol, amine in side chain R  Serine  Threonine  Tyrosine  Asparagines  Cysteine  Glutamine  Aspartic acid  Glutamic acid  Histidine  Lysine  Arginine  Non-polar amino acids: Pure hydrocarbon groups (aliphatic and aromatic) in side chain R  Glycine  Alanine  Valine  Leucine  Isoleucine  Phenylalanine  Tryptophan  Methionine  Proline
  • 10. Based On Their Nutritional Value  Essential amino acids: Can not be synthesized in human body and must be taken in diet.  Valine  Leucine *Arginine and histidine are essential in children, but not in adults.  Isoleucine  Phenylalanine  Methionine  Tryptophan  Threonine  Histidine  Lysine  Arginine  Non-essential amino acids: Can be synthesized in human body and hence they are non- essential in the diet. Alanine asparagine  Aspartic Acid  Glutamic Acid  Glutamine  Glycine  Proline  Serine  Cysteine  Tyrosine
  • 11. Based On Their Metabolic Fate  Glucogenic amino acids: Used for glucose synthesis only.  Glycine  Alanine  Methionine  Aspartic acid  Cysteine  Histidine  Glutamine  Arginine  Proline  Valine  Serine  Asparagine  Glutamic acid  Ketogenic amino acids: Used for ketone body synthesis only.  Lysine  Leucine  Ketogenic and glucogenic amino acids: Used for both ketone body synthesis and glucose synthesis.  Tryptophan  Tyrosine  Threonine  Isoleucine  Phenylalanine
  • 12. General properties of α-amino acids 1. Optical activity 2. Acid-Base properties of amino acids 3. Amphoteric properties of amino acids 4. Zwitterions form 5. Isoelectric point pI 6. Buffering capacity of amino acids 7. Physical properties of amino acids :
  • 13. Buffering capacity of amino acids Physical properties of amino acids  Amino acids are mainly water soluble.  They are soluble in polar solvents and not soluble in non-polar solvents.  They have high melting point.  A buffer is a solution which resists changes in 𝒑𝑯 when limited amount of acid or base is added to it.  A buffer is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid.
  • 14. Buffering capacity of amino acids  An amino acid has both an acidic group (carboxyl ) and a basic group (amine). Carboxyl group acts as conjugate acid (proton donor) and amino group acts as proton acceptor. Therefore together carboxyl group and amino group resists change in pH when small amount of acid or base is added.  For example glycine, glutamic acid and histidine use for preparation of buffer.
  • 15. Optical activity of amino acids  The ability of a substance to rotate plane-polarized monochromatic light is called optical activity.  The compound having carbon atom with four different groups is generally optically active.  All amino acids except glycine contain a tetrahedral carbon attached to four different groups (-COOH, -NH2, -R and –H).  In glycine, the tetrahedral carbon is attached to three different groups (-COOH, -NH2, and –H).  Therefore all amino acids except glycine is optically active.
  • 16. Acid-Base properties of amino acids  All amino acids contain at least two ionizable groups; an amine group (-NH2) and a carboxylic acid group (-CO2H).  Some amino acids contain an additional acidic (-CO2H) or basic group (-NH2) in their side chain, which are responsible for acid-base behaviour of amino acids.  Aspartic acid, glutamic acid are acidic amino acids.  Arginine, histidine, lysine are basic amino acids.  Other 15 amino acids are neutral.
  • 17. Zwitterions form of amino acids  A zwitterion is a neutral molecule with a positive and a negative electrical charge. All neutral amino acids are present in zwitterions form at physiological 𝐩𝐇 (around 7.4). H N H C H R C OH O H N + H C H R C O -- O H amino acid (free) amino acid (zwitter ion)  But acidic and basic amino acids form zwitter ions at different pH. R C COOH NH3 H R C COO -- NH3 H R C COO -- NH2 H pKa1 pKa2 H + HO -- + + at acidic pH (cation) at neutral pH (zwitterion) at basic pH (anion)
  • 18. Isoelectric point (𝐩𝐈) of amino acids  All amino acids have specific pH in which they form zwitter ion.  It is that 𝐩𝐇 at which net electrical charge of an amino acid is equal to zero ,and thus at this 𝐩𝐇 the amino acid can not move in an electric field.  𝐩𝐈 value varies from one amino acid to other. It is the average of two 𝒑𝑲𝒂 values. 𝐩𝐈 = 𝟏 𝟐 (𝒑𝑲𝒂𝟏 + 𝒑𝑲𝒂𝟐)
  • 19. R C COOH NH3 H R C COO -- NH3 H R C COO -- NH2 H pKa1 pKa2 H + HO -- + + at acidic pH (cation) at neutral pH (zwitterion) at basic pH (anion) Amphoteric properties An amphoteric species is a molecule or ion that can react as an acid as well as a base. Due to presence of ionizable amine and carboxylic acid groups, amino acids can act sometimes as acids and sometimes as bases depending on the 𝐩𝐇 of their media and isoelectric point. H+ donate: Acid H+ accept: Base OH- donate: base OH- accept: acid Electrons donate: Base Electrons accept: acid