أحمد محمود عيد 30104201601066

Kafrelsheikh University
Faculty of physical Therapy
Amino acids are the fundamental units of the proteins.
There are 300 amino acid occur in nature .only 20 of them occur in
mammalian proteins.
Other amino acids are found in a number of natural proteins.
Amino acid structure
Each amino acid has the following 4 groups or atoms attached to alpha
carbon atom.
1- Amino group
2- Carboxyl group
3- Hydrogen atom
4-Side chain or radical group
Proteins
Proteins are macromolecules formed of amino acids united together by
peptide bonds.
20 Amino acid are commonly found in proteins, in different proportions
are formed of two or more polypeptide chains.
The term protein is applied to describe molecules greater than 50 amino
acid
Molecules contain less than 50 amino acids are termed peptides
The 20amino acids characterized by:
-1They are all alpha amino acids (the amino group is attached to the alpha
carbon,next to the carboxyl group), except proline. Proline is not a
typical amino acid it is an imino acid as it contains imino group –NH
| P a g e 2