Copper protein

[1] Other copper proteins include some superoxide dismutases used in defense against free radicals, peptidyl-α-monooxygenase for the production of hormones, and tyrosinase, which affects skin pigmentation.

Example for Type-I blue copper protein are plastocyanine , azurin, and nitrite reductase, haemocyanin and tyrosinase.

[8] The Type 1 copper proteins are identified as blue copper proteins due to the ligand to metal charge transfer an intense band at 600 nm that gives the characteristic of a deep blue colour present in the electron absorption spectrum.

[10] The structure is very similar to plastocyanin and azurin as they also identify as Type 1 copper proteins.

The protein azurin has a trigonal bipyramidal geometry with elongated axial glycine and methoinione sulfur ligands.

However, in the blue copper protein case have low energy intense sigma and high energy weak π bonds because CT intensity reflects overlap of the donor and acceptor orbitals in the CT process.

This required that the 3d(x2-y2 ) orbital of the blue copper site be oriented such that its lobes bisect the Cu-S(Cys) bond giving dominant π overlap with sulfur directly.

Finally, the nature of the ground state wave function of the blue copper protein is rich in electron absorption spectrum.

The cysteine sulfur copper (II) ion bonds range from 2.6 to 3.2 Å.

With amicyanin, there is an exception due to the histidine being ligated and it is not bound to copper iodide.

In Figure 2, an energy level diagram shows three different relevant geometries and their d-orbital splitting and the Jahn-Teller effect is shown in blue.

(ii) shows the C3v symmetric geometry energy level splitting diagram with an 2E ground state that is degenerate.