3-[2-[(~{Z})-[5-[(4-ethenyl-3-methyl-5-oxidanylidene-pyrrol-2-ylidene)methyl]-3-(3-hydroxy-3-oxopropyl)-4-methyl-pyrrol-2-ylidene]methyl]-5-[(~{Z})-(3-ethyl-4-methyl-5-oxidanylidene-pyrrol-2-ylidene)methyl]-4-methyl-1~{H}-pyrrol-3-yl]propanoic acid; Biliverdine IX alpha, bound form