Molecular Aspects of a Robust Assay for Ferroxidase Function of Ceruloplasmin

Abstract

Ceruloplasmin (Cp) is one of the most complex multicopper oxidase enzymes and plays an essential role in the metabolism of iron in mammals. Ferrous ion supplied by the ferroportin exporter is converted by Cp to ferric ion that is accepted by plasma metallo-chaperone transferrin. Study of the enzyme at the atomic and molecular level has been hampered by the lack of a suitable ferrous substrate. We have developed the classic chromophoric complex FeIIHx(Tar)2 (H2Tar, 4-(2-thiazolylazo)resorcinol; x = 0-2; overall charge omitted) as a robust substrate for evaluation of the ferroxidase function of Cp and related enzymes. The catalysis can be followed conveniently in real time by monitoring the so..