[{"from": "human", "value": "Describe this molecule. [C][N][Branch2][Ring1][Branch2][C][C][=C][N][=C][C][=Branch1][Ring2][=N][Ring1][=Branch1][C][=Branch1][=Branch2][=N][C][=Branch1][Ring2][=N][Ring1][#Branch1][N][N][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][O]"}, {"from": "gpt", "value": "The molecule is a metabolite resulting from the carboxypeptidase-mediated cleavage of methotrexate. Deoxyaminopteroic acid can be used a marker for methotrexate exposure."}]