obsolete heavy metal binding true GO:0005505 heavy metal binding molecular_function OBSOLETE. Interacting selectively with a heavy metal, a metal that can form a coordination bond with a protein, as opposed to an alkali or alkaline-earth metal that can only form an ionic bond; this definition includes the following biologically relevant heavy metals: Cd, Co, Cu, Fe, Hg, Mn, Mo, Ni, V, W, Zn. This term was made obsolete because 'heavy metal' is an ambiguous grouping term which has no set meaning (see Pure Appl. Chem. Vol. 74, No. 5, pp. 793-807, 2002, for more information). metal ion binding