is deprotonated form of 6-aminopenicillanic acid 6-aminopenicillanate CHEBI:20704 (2S,5R,6R)-6-amino-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate (2S,5R,6R)-6-amino-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate CHEBI:12207 penicillinate anion 6-aminopenicillanic acid zwitterion