Deamination is the bodily process in which amino groups are removed from excess proteins. This happens most often in the liver, though it also occurs in the kidneys. This process allows the system to convert excess amino acids into usable resources such as hydrogen and carbon. The process also plays a vital role in removing nitrogen waste from the body. Amino groups discarded as a result of the process are converted into ammonia, which is later expelled from the body through urination.
Researchers believe that an overabundance of protein in the system can lead to several health issues. These include increased calcium excretion, heart disease, and even cancer. Excessive protein, if not offset by exercise, can also lead to unhealthy body weight. By removing the amino group, deamination converts excess protein into molecules the body can use for its other metabolic processes.
The chief site of deamination in the human body is the liver. Hydrolytic enzymes found in the organ separate the NH2 amino groups from proteins. The process leaves behind a carbon skeleton composed primarily of hydrogen, carbon, and oxygen. This skeleton can later be converted into usable glucose and lipids, indirectly making this process one of the body's energy-producing mechanisms.
Amino groups removed via deamination bond with a hydrogen molecule to form ammonia. Ammonia, however, is toxic to the human body and must be discarded. A separate chemical process combines the resulting ammonia with carbon dioxide, converting it into either urea or uric acid. Both compounds are diffused into the blood and later filtered out through the kidneys. The urea and uric acid are then expelled from the body via urination.
The kidneys also play an important role in breaking down amino acids. Excess glutamate undergoes deamination in the kidneys, wherein glutamate dehydrogenase catalyzes the process. As with liver deamination, the process forms ammonia, which is then discarded in the same fashion.
Although the process is generally beneficial to the human body, excessive deamination can prove to be a serious health risk. The increased activity in the liver and kidneys can wear down the organs, leading to significant damage and eventual failure. An overabundance in the resulting ammonia and uric acid can also pose health problems. In order to avoid this, some dietitians recommend limiting the amount of protein in the diet to levels near the recommended daily allowance. This is especially true for individuals who suffer from or have a family history of liver or kidney disease.