Deaminase is one of the enzymes involved in deamination, a process that, through hydrolysis, removes an amino group from a molecule. The primary way that deaminase removes an amino group is from extra proteins that occur in the liver or kidneys.
Deamination plays an important role in the body, helping to eliminate waste, and nitrogen waste, in particular. Deaminase removes the amino group and the nitrogen waste is converted to ammonia and then removed from the body through urination. The amino groups that are removed bond with a hydrogen molecule to form ammonia and a separate process then combines the ammonia with carbon dioxide, turning it into either urea or uric acid.
Deaminase also plays a role in converting the amino groups removed from proteins into different sources that the body can use. These include resources such as hydrogen and carbon, which are important to various different functions in the body. Ultimately, deaminase is important for keeping the body balanced and ensuring excess amounts of substances don't build up.
There are different types of deaminase which perform various roles in the body. For example, APOBEC3G, or A3G, plays a role in the cellular defence against HIV and its progression. The antiviral mechanisms of A3G can create mutations in the viral genome of HIV.
Although the main place where deamination occurs is in the liver, it also takes place in the kidneys. Glutamic acid is the most significant amino acid involved in deamination. Other amino acids are mostly deaminated through transamination and deamination of glutamate where glutamate recycles. Excess glutamate undergoes deamination in the kidneys, and glutamate dehydrogenase catalyzes the process. Histidase forms trans-urocanic acid by removing the amino group from histidine. This enzyme is found in the liver and skin. Deamination in the kidneys also produces ammonia, which is disposed of.
Adenosine or adenine deaminase (ADA) is involved in purine metabolism, breaking down adenosine from food. It is also necessary for the turnover of nucleic acids in tissues. It helps to develop and maintain the human immune system. ADA deaminates adenosine by substituting the amino group for a keto group and converting it into nucleoside inosine. ADA also converts deoxyadenosine to deoxyinosine.