Protein

Made from amino acids and therefore always contain the element carbon, hydrogen, oxygen and nitrogen, and in some cases sulphur.

Some proteins form complexes with other molecules containing phosphorus, iron, zinc and copper.

Macromolecules of high M, (relative formula mass or molecular mass between several thousands and several millions) consisting of chains of amino acids.

They are polymers and amino acids are the monomers. There are 20 different amino acids which are commonly found in naturally occurring proteins. The potential variety of proteins is unlimited because the sequence of amino acids in each protein is specific for that protein and is genetically controlled by the DNA of the cell in which it is made.

Proteins are the most abundant organic molecules to be found in cells and form over 50% of their total dry mass.

An essential component of the diet of animals and may be converted to both fat and carbohydrate by the cells.

Their diversity enables them to display a great range of structural and metabolic activities within the organism.