Metallothioneins have a high content of cysteine residues that bind various heavy metals; these proteins are transcriptionally regulated by both heavy metals and glucocorticoids. Metallothionein-IA Metallothionein-1A MT1A_HORSE MDPNCSCPTGGSCTCAGSCKCKECRCTSCKKSCCSCCPGGCARCAQGCVCKGASDKCSCCA 61