Blue copper fragmentation

When the complete amino acid sequence of ceruloplasmin was determined, an internal threefold repeat suggested gene triplication (Ta-kahashi et al., 1983). Moreover, sequence similarity to the small blue copper domains suggested that there were at least two domains with blue copper-binding sites. Analysis of fragments of laccase sequence indicated that there might be a relationship of this to small blue proteins and ceruloplasmin as well (Ryden, 1988). 

Thus, the two tetramine receptors cyclam and tren were linked by a 1, 4-xylyl spacer to give system 14, tren-cyclam. The heterodimetallic complex [Cu(II)(tren)-Ni(II)(cyclam]4+ operates chloride anion translocation between copper and nickel centers, through the Ni(II)/Ni(III) couple, in an MeCN solution [36]. In particular, when 1 equivalent of CP is added to an MeCN solution of the heterodimetallic complex [with the nickel center in the Ni(II) state], the anion goes on the Cu(II) ion. In particular, since the log K value for the 1 1 adduct formation equilibrium is 5.7, in a lO-3 M solution of the heterodimetallic complex, 95% of the CP ion is bound to Cu(II), while the remaining 5% is dispersed in the solution. The solution has a blue-green color, due to an absorption band centered at 460 nm, pertinent to the [Cu(II)(tren]2+ fragment of the heterodimetallic complex [Cl-to-Cu(II) CT transition). If in an... 

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