Amino Acid Structure And Formula

Amino Acid Structure And Formula


  • 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.

Also Read This ;-


  • 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.


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.

Based on polarity



Serine, Threonine, Glutamine, Asparagine, Cysteine.


a)Positively charged: Arginine, Lysine, Histidine.

b)Negatively charged: Glutamate, Aspartate.



Proline, Valine, Leucine, Isoleucine, Methionine.


Tyrosine, Phenylalanine, Tryptophan.

Amino Acid Structure And Formula
Amino Acid Structure And Formula Pdf
Shopping Cart
Scroll to Top