Gourt > Health > Conditions and Diseases > Genetic Disorders > Urea Cycle
The urea cycle, also known as the ornithine cycle, is a cycle of biochemical reactions occurring in many animal organisms that produces urea from ammonia (NH4+). This cycle was the first metabolic cycle discovered (Krebs and Hensenleit, 1932).
Function
Organisms that cannot easily and quickly remove ammonia usually have to convert it to some other substance, like urea or uric acid, which are much less toxic. Insufficiency of the urea cycle occurs in some genetic disorders (inborn errors of metabolism), and in liver failure. The result in liver failure is accumulation of nitrogenous waste, mainly ammonia, which leads to hepatic encephalopathy.
Reactions
The urea cycle consists of five reactions - two mitochondrial and three cytosolic. The cycle converts two amino groups, one from NH4+ and one from Asp, and a carbon atom from HCO3-, to relatively nontoxic excretion product, urea, at the cost of four "high-energy" phosphate bonds (3 ATP hydrolyzed to 2 ADP and one AMP). Orn is the carier of these carbon and nitrogen atoms. More on [ Urea cycle ]
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National Urea Cycle Disorders Foundation - Information about the organization as well as the disease. Family support, membership, newborn screening project and medical information.
Meta Description: [ The National Urea Cycle Disorders Foundation is a non-profit organization dedicated to the identification, treatment and cure of urea cycle disorders. ]
Urea Cycle Disorders - Information, medical links and a message board. The true story of a one family's struggle with this illness.
Meta Description: [ A site dedicated to raising awareness of Urea Cycle Disorders-a fatal, frequently overlooked disorder. Contains info on UCD's, and ordering info for the true story of a family's struggle to diagnose their son. ]
