Oxy hemocyanin

Figure 100 The dinuclear bridging unit in the met- and oxy-hemocyanin (a) dibridging and (b) monobridging1203...

Figure 5.1 Schematic representations of selected active sites of the copper proteins plastocyanin [56] (type 1, a) galactose oxidase [57] (type 2, b) oxy hemocyanin [58] (type 3, c) ascorbate oxidase [10] (type 4, or multicopper site, d) nitrous oxide reductase [59] (CuA site, e) cytochrome c oxidase [15]...

Figure 6-11 Structure of oxy-hemocyanin. (Reproduced with permission from Ref. 24.)...

At the same time when the first X-ray structure of an oxy-hemocyanin was published a side-on peroxo complex has successfully been prepared by Kitajima s group, which was commonly accepted but after strong discussions. This complex was found to be diamagnetic and showed spectral features remarkably similar to those of oxy-Hc s and Ty s. These also include the unusually low peroxo 0-0 stretching frequencies (<750 cm ) that appear to be characteristic for the structure. Finally, the side-on... 

Details about the spectroscopic characterization of the (p-rj rj -peroxo) dicopper(II) complexes are presented later. It has been noted that the dioxygen binding of tyrosinase is reversible as in the case of oxy-hemocyanin (Scheme i) 32,3s,36 fonn of the enzyme is converted into the... 

Figure 2-23. Structure of the active center of hemocyanine and oxy-hemocyanine containing O2 as r, ri -peroxide.

The VBCI model has been employed for the interpretation of the optical absorption and CD spectra of of peroxo bridged Cu dimers like oxy-Hemocyanin and corresponding small-molecule analogs (Figure 3).i "i 44-26 Hemocyanin (He), the oxygen-transport protein of mollusks and arthropods, contains a binuclear Cu(I) active site that reversibly binds dioxygen as peroxide in a... 

Optical absorption and CD spectrum of oxy-Hemocyanin and the model complex While the spectrum of oxy-Hc is typical for ii-rf. f Cu peroxo systems with an almost... 

Formation of metal-oxo species first became realistic in model studies on heme oxygenases (shunt path), and it has also become popular in nonheme systems. As for the metal-jd-peroxo species, the distinctive example of model study has appeared in the copper enzymes. The type 7 peroxo species has been proposed first based on models for dicopper oxy-hemocyanin [19, 20] before demonstration of the same oxygen bonding in enzyme [13]. The type 7 x-peroxo structure has been applied to diiron species in sMMO [14] in addition to 6 [21]. (see Chapter 8)... 

Figure 9. Active sites structures of deoxy- and oxy-hemocyanins, which may be resemble to those of tyrosinase [221].

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