arginase activity Catalysis of the reaction: L-arginine + H2O = L-ornithine + urea. EC:3.5.3.1 GO:0004053 L-arginase activity L-arginine amidinohydrolase activity MetaCyc:ARGINASE-RXN RHEA:20572 Reactome:REACT_104545 Reactome:REACT_105138 Reactome:REACT_105399 Reactome:REACT_112789 Reactome:REACT_115584 Reactome:REACT_21325 Reactome:REACT_29262 Reactome:REACT_394 Reactome:REACT_80504 Reactome:REACT_83897 Reactome:REACT_84916 Reactome:REACT_94417 Reactome:REACT_94917 Reactome:REACT_99000 Reactome:REACT_99109 Reactome:REACT_99872 arginine amidinase activity arginine transamidinase activity canavanase activity molecular_function