WP4595 - Urea cycle and associated pathways - Homo sapiens

The urea cycle converts toxic nitrogenous compounds to excretable urea in five biochemical reactions. It is also the source for endogenous arginine, ornithine and citrulline production. The process mainly takes place in the liver, partly in the mitochondria and partly in the cytoplasm of the hepatocytes. There are several pathways associated with the urea cycle and with the associated disorders, parts of these pathways are also pictured here.
Because there is no alternative way to convert toxic nitrogenous compounds, defects in the enzymes or transporters can lead to several diseases (diseases highlighted in pink). The diseases are characterised by hyperammonemia, respiratory alkalosis and encephalopathy and the severity of the disease depends on the severity of the defect and the place of the defect in the cycle. Severe forms usually have an onset in infancy, while mild forms can also present in adulthood.
This pathway was inspired by Chapter 4 of the book of Blau (ISBN 3642403360 (978-3642403361)).
For the Urea cycle without additional pathways see: [WP4571](https://wikipathways.org/pathways/WP4595)