 While hephaestin shares 50% amino acid sequence identity with its serum homologue ceruloplasmin, the hephaestin protein includes an additional 86 amino acids at the C-terminus, which code for a single transmembrane domain and a short cytoplasmic tail.While the structure and kinetic activity of ceruloplasmin have been studied extensively, hephaestin has yet to be investigated at a similar level.Comparative models of hephaestin's structure have been created using established crystallographic data from ceruloplasmin, and these studies suggest that many of the structural features important in the enzymatic function of the latter are also conserved in the former.