[{"from": "human", "value": "Describe this molecule. [B][Branch1][=C][C][C][S][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][N][Branch1][C][O][O]"}, {"from": "gpt", "value": "The molecule is l-cysteine substituted at sulfur by a 2-boronoethyl group. It is an organoboron compound, a L-cysteine thioether and a non-proteinogenic L-alpha-amino acid."}]