has role iron cation iron(2+) CAS:15438-31-0 CHEBI:49599 Fe(II) FE (II) ION Fe2+ Fe(2+) PDBeChem:FE2 CHEBI:29033 Gmelin:6845 CHEBI:13319 iron ion(2+) CHEBI:34754 Iron(2+) KEGG:C14818 CHEBI:24876 chebi_ontology CHEBI:21129 Ferrous ion CHEBI:13321 monoatomic dication divalent metal cation mouse metabolite Saccharomyces cerevisiae metabolite human metabolite