urea cycle

…reactions (now known as the urea cycle) by which ammonia is converted to urea in mammalian tissue; the urea, far less toxic than ammonia, is subsequently excreted in the urine of most mammals. This cycle also serves as a major source of the amino acid arginine.

…of urea, commonly called the urea cycle, is summarized as follows: Ammonia, formed from glutamate and NAD⁺ in the liver mitochondria (reaction [28]), reacts with carbon dioxide and ATP to form carbamoyl phosphate, ADP, and inorganic phosphate, as shown in reaction [30].

Liver cells play a critical role in disposing of nitrogenous waste by forming the compound urea (the primary solid component of urine) through the action of the urea cycle. When an amino acid is degraded, the ammonia nitrogen at one end of…