After digestion the proteins are converted into amino acids so that our cells can rebuild their own specific proteins.
The nitrogenated waste products are caused by cell degradation. The nitrogen comes from the amino acids and is eliminated by the urea.
There are three types of amino acids:
ESSENTIAL AMINO ACIDS:
The body cannot synthesise them. There are eight:
Leucine - Isoleucine - Lysine - Methionine - Phenylalanine - Threonine - Tryptophan - Valine.
NON-ESSENTIAL AMINO ACIDS:
Synthesised by the body from the essential amino acids. There are twelve:
Alanine - Aspartic acid - Glutamic acid - Cysteine - Cystine - Glycine - Hydroxyproline - Ornithin - Protine - Serine - Taurine - Tyrosine
SEMI--ESSENTIAL AMINO ACIDS:
Arginine - Histidine
Each amino acid plays a particular role in the body.
For example, arginine with methionine and glycine form creatine which is involved in muscular contraction.
Lysine is involved in muscular growth and tryptophan in the secretion of growth hormone.