Among the 25 known (natural) amino-acids certain may be synthesised in the body while others can't be synthesised in the body at a rate necessary for normal growth and hence must be supplied in the diet. Therefore, the first category of amino acids are called dispensable or non-essential amino-acids, while those of the second category are known as indispensable or essential amino acids. A deficiency in any one of the essential amino acids prevents growth in young animals and may even cause death. Although there are as much as ten essential amino acids to man; eight are more important while arginine and histidine are less important.
The important ten a-amino acids with their symbols are listed below :
| Theronine, |
Thr |
Methionine, |
Met |
| Valine, |
Val |
Phenylalanine |
Phe |
| Leucine, |
Leu |
Tryptophan |
Trp |
| Isoleucine, |
Ileu |
Arginine, |
Arg |
| Lysine, |
Lys |
Histidine, |
His |
Furthermore, it is important to note that the body can utilize completely only the natural L-(S) isomers1 of the essential amino-acids.
