[{"from": "human", "value": "Provide a brief overview of this molecule. [C][=C][C][=C][C][=Branch1][Ring2][=C][Ring1][=Branch1][C][=Branch1][Branch1][=C][N][Ring1][=Branch1][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][N]"}, {"from": "gpt", "value": "The molecule is the least plentiful of all 22 amino acids and an essential amino acid in humans (provided by food), Tryptophan is found in most proteins and a precursor of serotonin. Tryptophan is converted to 5-hydroxy-tryptophan (5-HTP), converted in turn to serotonin, a neurotransmitter essential in regulating appetite, sleep, mood, and pain. Tryptophan is a natural sedative and present in dairy products, meats, brown rice, fish, and soybeans. (NCI04)"}]