Copper electron transfer

Blue copper electron transfer proteins, 6,712-717 Blue copper oxidases, 6,699 Blue copper proteins, 2, 557 6, 649 Blue electron transfer proteins, 6,649,652 spectroscopy, 6, 651 Blue oxidases copper, 6,654,655 Blueprint process, 6,124 Blue proteins model studies, 6,653 Boleite... 

Several copper enzymes will be discussed in detail in subsequent sections of this chapter. Information about major classes of copper enzymes, most of which will not be discussed, is collected in Table 5.1 as adapted from Chapter 14 of reference 49. Table 1 of reference 4 describes additional copper proteins such as the blue copper electron transfer proteins stellacyanin, amicyanin, auracyanin, rusticyanin, and so on. Nitrite reductase contains both normal and blue copper enzymes and facilitates the important biological reaction NO) — NO. Solomon s Chemical Reviews article4 contains extensive information on ligand field theory in relation to ground-state electronic properties of copper complexes and the application of... 

Ceruloplasmin is involved in copper storage and transport as well as in iron mobilisation and oxidation. Among the blue oxidases it is unique since it contains, in addition to the usual motif of a type 1 combined with the trinuclear cluster, two other type 1 coppers. Electron transfer occurs, however, only between five of the six copper ions since one of the type 1 centres is not catalytically relevant due to its too high redox potential. The redox potentials of the centres were determined and possible electron transfer pathways among the copper sites were discussed.101... 

Some progress has been made in the characterization of the redox centres. The presence of a potential type 1 blue copper site in subunit I is in accord with EXAFS data that have demonstrated Cu—S interactions, in particular the possibility of two sulfur atoms bound to CuA.1309 It seems possible therefore that CuA is a type 1 copper, typical of copper electron-transfer proteins. The nature of CuB is less certain ESR parameters indicate that CuB is similar to type 3 copper, which occurs pairwise in copper oxidases as the 02-binding site. 

Francisco WA, WiUe G, Smith AJ, Merkler DJ, Klinman JP. Investigation of the pathway for inter-copper electron transfer in peptidyglycine alpha-amidating monooxygenase. J. Am. Chem. Soc. 2004 126 13168-13169. 

In the Sandmeyer reactions involving copper, electron-transfer-mediated radical reactions are certainly involved. In HCI, cuprous chloride (CuCl) is in equifib-rium with the dichlorocuprate ion CuCl2 (Frg. 14.56).The dichlorocuprate ion can transfer an electron to the diazonium ion, which can then lose molecular nitrogen to give a phenyl radical. In turn, the phenyl radical can pluck a chlorine atom from a copper chloride molecule to give the chlorobenzene and a molecule of cuprous chloride. The mechanism for the formation of chlorobenzene in the Sandmeyer reaction is shown in Figure 14.57. 

Farrar JA, Neese F, Lappalainen P, Kroneck PMH, Saraste M, Zumft WG, Thomson AJ. 1996. The electronic structure of Cua a novel mixed-valence dinuclear copper electron transfer center. JAm Chem Soc 118 11501-11514. 

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