Welcome to class of Amino Acids Dr Meera

  • Slides: 26
Download presentation
Welcome to class of Amino Acids Dr. Meera Kaur

Welcome to class of Amino Acids Dr. Meera Kaur

Learning objectives • To understand - the structural features of amino acids - the

Learning objectives • To understand - the structural features of amino acids - the classifications of amino acids - the properties of amino acids

Introduction • Amino acids are the building block of protein • There are 20

Introduction • Amino acids are the building block of protein • There are 20 naturally occurring amino acids In the following slides, we shall discuss about the structural features, classifications and properties of amino acids.

Structural features of Amino acids • All 20 amino acids have common structural features

Structural features of Amino acids • All 20 amino acids have common structural features • All amino acids have an amino group (-NH 3+), a carboxylate (-COO-) group and a hydrogen bonded to the same carbon atom (the -carbon) • They differ from each other in their side chain called R group. • R groups vary in structure, size and electric charges and influence the solubility of amino acids in water.

Structure of Amino acid

Structure of Amino acid

Classification of Amino Acids • Nutritional - Essential - Non-essential Based on R group

Classification of Amino Acids • Nutritional - Essential - Non-essential Based on R group - Non polar aliphatic R group - Polar uncharged R group - Aromatic R group - Positively charged R group - Negatively charged R group

The hydrocarbon R group in this class of amino acids is nonpolar and hydrophobic.

The hydrocarbon R group in this class of amino acids is nonpolar and hydrophobic. Glycine has the simplest amino acid structure. The bulky side chain of valine, isoleucine and leucine are important in promoting hydrophobic interactions within protein structures.

The R group of these amino acids is more soluble in water, or hydrophilic

The R group of these amino acids is more soluble in water, or hydrophilic than those of non polar amino acids, because they contain functional groups that form hydrogen bond with water

Their aromatic side chains are relatively nonpolar. All can participate in hydrophobic interactions. The

Their aromatic side chains are relatively nonpolar. All can participate in hydrophobic interactions. The OH group of tyrosine can form hydrogen bond and can act as an important functional group in the activity of some enzymes.

The amino acids in which the R group have a net positive charge at

The amino acids in which the R group have a net positive charge at p. H 7. 0

Amino acids having R group with a net negative charge at p. H 7.

Amino acids having R group with a net negative charge at p. H 7. 0, with a second carboxyl group

Structures and abbreviations of the standard amino acids

Structures and abbreviations of the standard amino acids

Nutritional Classification of Amino acids Essential Amino Acids: Nonessential Amino Acids: Need to supplied

Nutritional Classification of Amino acids Essential Amino Acids: Nonessential Amino Acids: Need to supplied in daily diet 1. Lysine 2. Leucine 3. Isoleucine 4. Metionine 5. Tryptophan 6. Phenylalanine 7. Threonine 8. Valine Need not be supplied in daily diet • Alanine • Asparagine • Glycine • Tyrosine • Serine • Proline • Cysteine • Cystine • Histidine(essential for children) • Glutamine(conditionally essential) • Arginine(conditionally essential) • Glutamate

Properties of amino acids… - All the amino acids except glycine have handedness (chiral)

Properties of amino acids… - All the amino acids except glycine have handedness (chiral) Amino acids exist as D or L form that are nonsuperimposable mirror image of one another – L-form naturally occurs in proteins

Structure of Amino acid (projection formula) Horizontal bonds are assumed to project out of

Structure of Amino acid (projection formula) Horizontal bonds are assumed to project out of the plane of the paper, the vertical bond behind

Handedness of Amino Acids Perspective formula: the wedge-shaped bonds project out of the plane

Handedness of Amino Acids Perspective formula: the wedge-shaped bonds project out of the plane of the paper and the dashed bonds behind it.

Properties of Amino Acids… • Amino acids form internal salts called zwitterions • In

Properties of Amino Acids… • Amino acids form internal salts called zwitterions • In the pure solid state and in aqueous solution near neutral p. H, amino acids exist almost completely as zwitterions

Properties of Amino Acids… • In zwitterions of amino acids with uncharged side chain,

Properties of Amino Acids… • In zwitterions of amino acids with uncharged side chain, the +ve and –ve Charges cancel one another • Amino acids in which the +ve and –ve charges are balanced is at its isoelectric point • The p. H at which this balancing occurs is isoelectric p. H • An amino acids is least soluble at its isoelectric p. H • Increases solubility at lower p. H as well as at higher p. H

Properties of Amino Acids • Amino Acids are linked to form peptide • The

Properties of Amino Acids • Amino Acids are linked to form peptide • The condensation of the carboxylic group of one amino acid with the amino group of another amino acid releases a water molecule and forms a peptide bond or peptide link

Condensation reaction

Condensation reaction

Formation of a peptide bond

Formation of a peptide bond

Amino acid residues

Amino acid residues

Peptide Bond

Peptide Bond

Amino Acids Amino Acids Amino Acids Amino AcidsAmino Acids Amino Acids Amino Acids Amino Acids
Amino Acids Amino Acids Amino acids are buildingAmino Acids Amino Acids Amino acids are building
Amino acids Proteins Amino Acids Amino acids AreAmino acids Proteins Amino Acids Amino acids Are
Amino acids Essential Amino Acids 10 amino acidsAmino acids Essential Amino Acids 10 amino acids
Amino acids Proteins Amino Acids Amino acids AreAmino acids Proteins Amino Acids Amino acids Are
Amino Acid Synthesis Essential Amino Acids amino acidsAmino Acid Synthesis Essential Amino Acids amino acids
AMINO ACIDS Qualitative Tests Amino Acids Amino acidAMINO ACIDS Qualitative Tests Amino Acids Amino acid
Qualitative tests of amino acids Amino acids AminoQualitative tests of amino acids Amino acids Amino
Welcome to class of Amino Acids Dr MeeraWelcome to class of Amino Acids Dr Meera
Amino Acid Metabolism Essential Amino Acids Essential aminoAmino Acid Metabolism Essential Amino Acids Essential amino
Amino acid Productions Amino acid Amino Acids AreAmino acid Productions Amino acid Amino Acids Are
AMINO ACIDS STRUCTURAL UNITS OF PROTEINS AMINO ACIDSAMINO ACIDS STRUCTURAL UNITS OF PROTEINS AMINO ACIDS
AMINO ACIDS AMINO ACIDS the R group variesAMINO ACIDS AMINO ACIDS the R group varies
Amino Acids When you understand the amino acidsAmino Acids When you understand the amino acids
4 AMINO ACIDS 1 INTRODUCTION Amino acids serve4 AMINO ACIDS 1 INTRODUCTION Amino acids serve
Proteins from Amino Acids Two amino acids joinedProteins from Amino Acids Two amino acids joined
Amino Acids 1292003 Amino Acids The building blocksAmino Acids 1292003 Amino Acids The building blocks
Amino Acids Disposal of Nitrogen Overview Amino acidsAmino Acids Disposal of Nitrogen Overview Amino acids
AMINO ACIDS 5 6 NB 20 amino acidsAMINO ACIDS 5 6 NB 20 amino acids
Classification of amino acids Amino acids are classifiedClassification of amino acids Amino acids are classified
Amino Acids When you understand the amino acidsAmino Acids When you understand the amino acids
Amino Acids When you understand the amino acidsAmino Acids When you understand the amino acids
Amino Acids Peptides Proteins Amino Acids Zwitterion orAmino Acids Peptides Proteins Amino Acids Zwitterion or
Definitions Amino Acids a a Amino Acids areDefinitions Amino Acids a a Amino Acids are