The end product of protein metabolism is typically nitrogenous waste in the form of ammonia, urea or uric acid. If it is not properly excreted from the body, these substances may build up in the body's systems and result in health issues.
Nitrogen is essential to biological functions, and its utilization through protein metabolism yields waste products. Uric acid is produced by the breaking down of substances known as purines, which are found in food. Ammonia is produced when the body performs the synthesis of amino acids and nucleotides, which are genetic materials essential for the creation of new life. The accumulation of these substances are removed through the body's excretory system when necessary.