A comparison of ceruloplasmin to biological polyanions in promoting the oxidation of Fe2 under physiologically relevant conditions

Abstract

Background Iron oxidation is thought to be predominantly handled enzymatically in the body, to minimize spontaneous combustion with oxygen and to facilitate cellular iron export by loading transferrin. This process may be impaired in disease, and requires more accurate analytical assays to interrogate enzymatic- and auto-oxidation within a physiologically relevant environment. Method A new triplex ferroxidase activity assay has been developed that overcomes the previous assay limitations of measuring iron oxidation at a physiologically relevant pH and salinity. Results Revised enzymatic kinetics for ceruloplasmin (Vmax≈ 35 μM Fe3 +/min/μM; Km≈ 15 μM) are provided under physiological conditio..