<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> Deamination is the removal of an amino group from a molecule . Enzymes that catalyse this reaction are called deaminases . </P> <P> In the human body, deamination takes place primarily in the liver, however glutamate is also deaminated in the kidneys . In situations of excess protein intake, deamination is used to break down amino acids for energy . The amino group is removed from the amino acid and converted to ammonia . The rest of the amino acid is made up of mostly carbon and hydrogen, and is recycled or oxidized for energy . Ammonia is toxic to the human system, and enzymes convert it to urea or uric acid by addition of carbon dioxide molecules (which is not considered a deamination process) in the urea cycle, which also takes place in the liver . Urea and uric acid can safely diffuse into the blood and then be excreted in urine . </P> <P> Spontaneous deamination is the hydrolysis reaction of cytosine into uracil, releasing ammonia in the process . This can occur in vitro through the use of bisulfite, which deaminates cytosine, but not 5 - methylcytosine . This property has allowed researchers to sequence methylated DNA to distinguish non-methylated cytosine (shown up as uracil) and methylated cytosine (unaltered). </P>

Where are unwanted amino acids converted into urea