Type 1,2,3 copper

Copper (type III) in oxidases Open-sided pair of tetrahedra... 

Since the first EPR work on Cu(II) ions in proteins in the late fifties193, a great many EPR investigations on copper-containing proteins have been reported194-198. For a classification of the copper proteins into type I (blue copper), type II (non-blue copper) and type III (binuclear cupric pair), the reader is referred to Fee197. ... 

Characterization of the Type 2 Depleted Derivative of Laccase. The model for the coupled blnuclear copper site in hemocyanln and tyrosinase (Figure 7) may now be compared to the parallel site in laccase which contains a blue copper (denoted Type 1 or Tl), a normal copper (Type 2, T2), and a coupled binuclear copper (Type 3, T3) center. As shown in Figures 8a and b, native laccase has contributions from both the Tl and T2 copper centers in the EPR spectrum (the T3 cupric ions are coupled and hence EPR nondetectable as in hemocyanln), and an intense absorption band at associated with the Tl center (a thlolate —> Cu(II) CT transition).(14) The only feature in the native laccase spectra believed to be associated with the T3 center was the absorption band at 330 nm (e 3200 M cm ) which reduced with two electrons, independent of the EPR signals.(15) Initial studies have focussed on the simplified Type 2 depleted (T2D) derlvatlve(16) in which the T2 center has been reversibly removed. From Figure 8 the T2 contribution is clearly eliminated from the EPR spectrum of T2D and the Tl contribution to both the EPR and absorption spectrum remains. 

Chlorine is the major anion in surface- and mantle-derived fluids. It is the most abundant anion in hydrothermal solutions and is the dominant metal complexing agent in ore forming environments (Banks et al. 2000). Despite its variable occurrence, chlorine isotope variations in natural waters conunonly are small and close to the chlorine isotope composition of the ocean. This is also true for chlorine from fluid inclusions in hydrothermal minerals which indicate no significant differences between different types of ore deposits such as Mississippi-Valley and Porphyry Copper type deposits (Eastoe et al. 1989 Eastoe and Guilbert 1992). 

Moir, W. B., Baratta, D., Richardson, D. J., and Ferguson, S. ]. (1993). The purification of a cd -type nitrite reductase from, and the absence of a copper-type nitrite reductase from, the aerobic denitrifier Thiosphaera pantotropha. Eur. J. Biochem. 212, 377-385. 

Figure 8. Proposed electron transfer pathway in blue copper proteins. The plastocyanin wave function contours have been superimposed on the blue copper (type 1) site in ascorbate oxidase (40). The contour shows the substantial electron delocalization onto the cysteine Spir orbital that activates electron transfer to the trinuclear copper cluster at 12.5 A from the blue copper site. This low-energy, intense Cys Sp - Cu charge-transfer transition provides an effective hole superexchange mechanism for rapid long-range electron transfer between these sites (2, 3, 28).

The range of observed values for the H NMR shifts and for linewidths in the various copper types is summarized in Table I. 

Copper Types, Coordination Geometries, Donor Atoms, and NMR Parameters in Copper(II) Proteins... 

For the subsequent slower reductions of both the 610- and 330-nm chromophores, similar maximum rate constants were obtained. This result indicates that at high substrate concentrations the reduction of both copper types may be limited by a common rate-determining step. 

Since the early days of texture research the fact that fee metals and alloys develop two different types of rolling texture, the copper type and the brass type, has been a mystery to the texture community. One may say that it is the classical texture problem. As mentioned in section 1 it was already in the nineteensixties suggested, on the basis of circumstantial evidence, that the texture transition is governed by cross slip. In 1968 one of the present... 

The cubic closed ABC type packing (ccp) or cubic face centered structure is realized in nature by metals like gold, silver, copper, lead, aluminum, nickel and many other metals based on the importance of the metal copper, it is called the Copper Type (see Fig. 5.6). 

The properties of Type 2 copper in blue-copper oxidases contrast sharply with those of Type 1 copper in this class of enzymes. The optical (weak visible absorbance) and EPR (0.015 cm Aj <0.020 cm ) spectra clearly resemble those encountered for Cu(II) copper in low molecular weight tetragonal complexes. Despite its prosaic spectroscopy, Type 2 copper chemistry appears to be richer than that of Type 1 copper. Type 2 copper will bind exogeneous ligands at both axial and equitorial positions and is accessible to water in the solvent milieu. In blue copper oxidases, this lability to ligand exchange is used to stabilize an intermediate in the course of O2 reduction (see below). 

In general, the noble-metal catal3 ts, such as platinum or palladium, are used from room temperatures to 150°C catalysts of the nickel and copper type, from 150-260 C and various combinations of metals and metal oxides, from 250-400 C. 

Biological copper types I-III physical and chemical characteristics " ... 

Recently several laccases have been crystallized and their three-dimensional crystal structures are now available 13,33-35). Laccase belongs to the class of multicopper-oxidases and contains four copper centers per protein molecule type 1 (Tl) or blue copper, type 2 (T2) or normal copper, and type 3 (T3) or coupled dinuclear copper centers 36). It catalyzes the oxidation of electron rich aromatic substrates, usually phenols or aromatic amines, via four single electron oxidation steps concomitant with the four electron reduction of O2 to H2O 15,37). Electron transfer takes place at the Tl site, which is followed by electron transfer to the T2/T3 assembly. This is where the reduction of dioxygen takes place. 

Titanium Bronze Brass Carbon steel Nickel-copper alloy Copper Type 304 SS Series 400 SS... 

Tyrosinase-catalyzed transformations of catechols and o-benzoquinones were modeled by copper complexes which mimic both the spectroscopic characteristics [44-48] and the chemical behavior [49,50] of the biological systems. Tyrosinases have so-called copper type 3 centers, which are strongly antiferromagnetically coupled. The multicopper concept has emerged as an important feature in the modeling approach. 

The high-copper type is available in two alloy groups, classified by the mixture of different powder shapes ... 

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