Amino Acid are building blocks of proteins. Each amino acid contains a carboxyl group(COOH) or an acidic group and an amino (NH2) group or a basic group.The basic amino acid structure is R-CH(NH2)-COOH. Amino acids consist of the following elements: carbon, hydrogen, oxygen, nitrogen, and, sometimes, sulfur.There are 21 amino acids in all.The general structure of amino acids consists of a carbon center and its four substituents, which consists of an amino group (NH2), an organic acid (carboxyl) group (COOH), a hydrogen atom (H), and a fourth group, referred to as the R-group, that determines the structural identity and chemical properties of the amino acid. The first three groups are common to all amino acids. There are two types of amino acids:
- Essential amino acids (EAA) – cannot be synthesized by the body and their requirement has to be met through dietary intake. In all there are 9 essential amino acids for human adults.
Nine essential amino acids are- Methionine
Threonine
Isoleucine
Leucine
Lysine
Tryptophan
Valine
Phenylalanine
Arginine
Histidine is an essential amino acid for human infants and non essential for the adults
2. Non essential amino acids- can be synthesized by the body and they need not to be supplied through diet. Cystine
cysteine
Proline
Glycine
Serine
Alanine
Glutamine
Hydroxyproline
Tyrosine