Ceruloplasmin structural data

Table 5.2 contains data about selected copper enzymes from the references noted. It should be understood that enzymes from different sources—that is, azurin from Alcaligenes denitrificans versus Pseudomonas aeruginosa, fungal versus tree laccase, or arthropodan versus molluscan hemocyanin—will differ from each other to various degrees. Azurins have similar tertiary structures—in contrast to arthropodan and molluscan hemocyanins, whose tertiary and quaternary structures show large deviations. Most copper enzymes contain one type of copper center, but laccase, ascorbate oxidase, and ceruloplasmin contain Type I, Type II, and Type III centers. For a more complete and specific listing of copper enzyme properties, see, for instance, the review article by Solomon et al.4... 

Native porcine ceruloplasmin showed small CD bands in the visible region, which disappeared on removal or reduction of the copper. Far ultraviolet CD and ORD data indicated the presence of and random structures (97). Several CD bands were recorded for human ceruloplasmin (pH 5.5) in the range 300 to 1100 nm. Spectral changes were observed upon addition of azide (98). 

ORD and EPR measurements indicated that the ligand field of the single cupric ion is distorted from the regular square-planar configuration [(109) and refs, cited therein similar considerations had been applied to the Cu(II) sites in the copper protein ceruloplasmin (96)]. This could also explain the very intense blue color observed. ORD data in the ultraviolet region indicated little or no helical structure in this plant protein (109). CD spectra of stellacyanin in the range 300 to 1100 nm were reported (98). 

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