[{"from": "human", "value": "Provide a brief overview of this molecule. [C][Branch1][O][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][N][C][N][C][=Branch1][C][=O][N]"}, {"from": "gpt", "value": "The molecule is an amino acid.  It is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle. It is also produced from arginine as a by-product of the reaction catalyzed by NOS family.  Its name is derived from citrullus, the Latin word for watermelon, from which it was first isolated."}]