title: Coagulation Factor V contains copper ion.
abstract: Preparations of bovine and human coagulation Factor V were analyzed for copper using both atomic absorption and atomic emission spectroscopy. All preparations of the bovine and human protein were found to contain copper ion at a ratio of 1 copper ion bound per mol (Mr = 330,000) of Factor V. As a result of copper binding and sequence homology between ceruloplasmin and Factor V, bovine Factor V and thrombin-activated Factor V (Va) were assessed with respect to their visible and near ultraviolet absorption spectra and to their ability to oxidize N,N-dimethyl-p-phenylenediamine (a substrate for ceruloplasmin). Factor V and Factor Va exhibited absorption spectra with no maxima at either 310 or 610 nm, indicating that the copper is not bound in a site analogous to Type I or Type III copper sites in ceruloplasmin. Further, Factor V and Factor Va are not capable of serving as catalysts for the oxidation of N,N-dimethyl-p-phenylenediamine under solution conditions that are optimum for ceruloplasmin oxidase activity. These data suggest that the copper ion bound to Factor V may be functionally and structurally distinct from the Type I and Type III copper ion bound to ceruloplasmin.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003300:Copper / Q000032:analysis*; D005165:Factor V; D015943:Factor Va; D006801:Humans; D008970:Molecular Weight; D011485:Protein Binding; D013045:Species Specificity; D013053:Spectrophotometry; D013054:Spectrophotometry, Atomic
chemical_list: D015943:Factor Va; D003300:Copper; D005165:Factor V