| ULS00179 | (N(omega)-L-arginino)succinate from L-aspartate and L-citrulline | None - {{∅}} | True - {{t}} | Unconfirmed presence |  | 
                
                    | UPA00158 | 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) [Wikipedia]. Arginine from the diet or from protein breakdown is cleaved by the cytosolic enzyme arginase, generating urea and ornithine. In subsequent reactions of the urea cycle a new urea residue is built on the ornithine, regenerating arginine and perpetuating the cycle. | None - {{∅}} | None - {{∅},{t}} | Unexplained |  | 
                
                    | ULS00180 | L-arginine and fumarate from (N(omega)-L-arginino)succinate | None - {{∅}} | True - {{t}} | Unconfirmed presence |  | 
                
                    | MUER6 | Meta-UER 6~1 ATP + 1 L-aspartate + 1 L-citrulline => 1 (N(omega)-L-arginino)succinate + 1 AMP + 1 diphosphate. | True - {{∅},{t}} | True - {{t}} | Confirmed presence |  | 
                
                    | UER00270 | L-ornithine and urea from L-arginine: step 1/1~1 H(2)O + 1 L-arginine => 1 L-ornithine + 1 urea. | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | ULS00178 | L-citrulline from L-ornithine and carbamoyl phosphate | None - {{∅}} | True - {{t}} | Unconfirmed presence |  | 
                
                    | MUER3 | Meta-UER 3~1 (N(omega)-L-arginino)succinate => 1 L-arginine + 1 fumarate. | True - {{∅},{t}} | True - {{t}} | Confirmed presence |  | 
                
                    | ULS00177 | L-ornithine and urea from L-arginine | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | MUER13 | Meta-UER 13~1 L-ornithine + 1 carbamoyl phosphate => 1 L-citrulline + 1 phosphate. | True - {{∅},{t}} | True - {{t}} | Confirmed presence |  |