General Description
Arginase is a manganese-containing enzyme that catalyzes the conversion of arginine to urea and ornithine. Two isoforms of arginase are present in most mammals which differ in their tissue distribution and subcellular localization. Arginase I is a cytoplasmic protein predominantly expressed in the liver where it catalyzes the fifth and final step of the Urea Cycle. Arginase II is a mitochondrial protein with broader tissue distribution whose function may include nitric oxide and polyamine metabolism. Decreased activity or expression of Arginase I results in the autosomal recessive disorder hyperarginemia. Increased serum Arginase activity is implicated in hepatic injury and in certain pathological conditions such as cancer. Arginase also participates in multiple inflammatory reactions in the immune system, such as macrophage-mediated cytotoxicity.
