Amino Acid Structure And Formula

DEFINITIONS

A protein molecule consists of one or more long unbranched polymer chains composed of numerous small subunits or monomers is called amino acids.
There are 20 amino acids from which 18 have the same structure.

LINKAGE OF AMINO ACIDS

In protein, the amino acids link up in such a way that the amino group of one amino acid is joined to the carboxyl group of the adjacent one with the loss of water molecule for each linkage as a byproduct.
The amino group contributes hydrogen and the carboxyl group contributes hydroxyl group (-OH) to water.
The covalent bond joining the two amino acid unit by –NH-CO linkage is called Peptide Bond. It is formed by the process of condensation ( Dehydration ) i.e loss of water.
A chain of two amino acids is called Dipeptide. A chain of three amino acid is called Tripeptide, of a few ( less than 30 ), Amino acid and Oligopeptide, and of many ( more than 30 ), Amino acid are Polypeptide.

FUNCTION Of Amino Acid

Essential

VALINE: Helps in the growth of muscles.
ISOLEUCINE: Plays a vital role in the synthesis of hemoglobin and its major component of RBC.
METHIONINE: Helps in maintaining good and healthy skin.
LEUCINE: It promotes the synthesis of growth hormones.
LYSINE: They are involved in the synthesis of enzymes and other hormones.
HISTIDINE: Helps in the production and synthesis of both RBC and WBC.

Non- essential

ALANINE: Helps in the removal of toxins from our body.
CYSTEINE: Provides resistance to our body and inhibits the growth hairs, nails and etc.
GLYCINE: It acts as a neurotransmitter and plays a vital role in healing wounds.
ARGININE: It promotes the biosynthesis of proteins.
TYROSINE: It plays a vital in the production of T3 and T4 thyroid hormones.

CLASSIFICATION Of Amino Acid

Based on nature

ACIDIC AMINO ACIDS: These contain one amino group and two carboxyl groups per molecule. These are called monoamine-dicarboxylic amino acids. Example – Aspartic acid, Glutamic acid.

BASIC AMINO ACIDS: These contain two amino groups and one carboxyl group per molecule. These are called as diamino- monocarboxylic amino acids. Example – Lysine, Arginine.

NEUTRAL AMINO ACIDS: These have one amino group and one carboxylic group per molecule. These are called monoamine- monocarboxylic amino acids. Example – Glycine, Valine.

Based on the special structure

SULPHUR CONTAINING AMINO ACIDS: These amino acids contain sulfur.

Example: Methionine, Cysteine.

ALCOHOLIC AMINO ACIDS: These amino acids contain an alcoholic group.

Example – Serine, Threonine, Tyrosine.

AROMATIC AMINO ACIDS: These amino acids contain phenyl rings.

Example – Phenylalanine, Tryptophan

HETEROCYCLIC AMINO ACIDS: These amino acids contain a heterocyclic ring.

Example – Proline

Based on nutritional requirement

ESSENTIAL AMINO ACIDS: There are a few amino acids that cannot be synthesized by the body.

Examples: Phenylalanine, Valine, Leucine, Lysine, Methionine, Histidine.

NON ESSENTIAL AMINO ACIDS: There are few amino acids which are easily biosynthesized by our body.

Examples: Alanine, Cysteine, Cystine, Glutamine, Glycine, Glutamate, Arginine, Tyrosine, Serine, Asparagine, Aspartic acid, Proline.