The urea cycle enzyme arginase (EC ) hydrolyzes L-arginine to L-ornithine and urea. Mammalian arginases require manganese, have a highly alkaline pH optimum and are resistant to reducing agents. The gastric human pathogen,Helicobacter pylori, also has a complete urea cycle and contains therocFgene encoding arginase (RocF), which is involved in the pathogenesis ofH. pyloriinfection. Its arginase is specifically involved in acid resistance and inhibits host nitric oxide production.
