The molecule is a dicarboxylic acid anion obtained by deprotonation of the carboxy groups of ferriheme a3. Major structure at pH 7.3. It is a conjugate base of a ferriheme a3.
3-[18-(2-carboxylatoethyl)-7-ethenyl-17-formyl-12-[(1S)-1-hydroxy-5,9,13-trimethyltetradecyl]-3,8,13-trimethylporphyrin-21,23-diid-2-yl]propanoate;iron(3+)