Deamination

Deamination is the process that removes an Amine group from a molecule.

Deamination of Nucleotide Bases:

Removing an amine group from a base can alter its structure.

Deamination of Cytosine transforms it into Uracil

Deamination of Adenine transforms it into Hypoxanthine

Deamination of Guanine transforms it into Thymine 

Deamination of Amino Acids:

Involves removing NH₂ (amino group) from an amino acid and forming ammonia (NH₃) by reacting the amino acid with oxygen .

The organic acid containing an oxygen with a double bond is usually respired.

Ammonia is a toxic substance to the body and is converted quickly into urea which is less harmful.  The kidneys remove urea from the body.