Isolation and characterization of metallothionein dimers.

The dimeric forms of metallothionein were isolated from livers of rabbits which accumulated cadmium in large quantities. The dimers were separated into three isoproteins, both on a DEAE Sephadex A-25 column and on a gel permeation column. Reduction of each dimer with mercaptoethanol yielded monomeric metallothionein-I, an equivalent mixture of metallothionein-I and -II, and metallothionein-II. The three isoproteins were identified as a dimer of metallothionein-I, a dimer of metallothionein-I and -II, and a dimer of metallothionein-II, respectively.