MT1A binds 7 atoms of cadmium(II), 3 atoms at the N-terminal beta domain and 4 atoms at the C-terminal alpha domain (Rigby Duncan et al. 2008, Sunderland and Stillman 2008, Sutherland et al. 2012). A fifth cadmium atom bound to the alpha domain may be an intermediate formed during metal exchange (Rigby Duncan et al. 2008). Binding of cadmium is non-cooperative (Rigby Duncan and Stillman 2007, Sunderland and Stillman 2008). As inferred from mouse Mt1, MT1A may show less preference for zinc compared with cadmium and may therefore serve more than other metallothionein isoforms to detoxify cadmium.