[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is the zwitterion from the dipeptide glycylglycine formed by proton transfer from the OH of the carboxy group to the terminal amino group. It has a role as a human metabolite. It is a tautomer of a glycylglycine."}, {"from": "gpt", "value": "[C][Branch1][N][C][=Branch1][C][=O][N][C][C][=Branch1][C][=O][O-1][NH3+1]"}]