Cytochrome c Oxidase Model Compounds and Associated Analytical Techniques

4 Cytochrome c Oxidase Model Compounds and Associated Analytical Techniques 

In 2004, Kenneth Karlin and co-workers published an extensive review of cytochrome c oxidase model compounds. Hundreds of CcO models exist, with more being synthesized and studied into the current time. These can be broken down into a number of categories as Karlin s group does in the 2004 

Chemical Reviews paper. We can only discuss a small number of these here, but some important categories are (1) synthetic Fe(II)-Cu(I) complexes and their reactions with O2, (2) oxidized heme-copper models (Fe(III)-X-Cu(II) complexes, where X equals 0x0- and hydroxo-bridged complexes, cyanide-bridged complexes, or other X-bridged complexes), (3) crosslinked histidine-tyrosine residues at the heme-copper center, and (4) Cua site synthetic models. 

The product was identihed by a number of spectroscopic methods. Dioxygen uptake was measured by spectrophotometric titration. MALDI-TOF-MS (matrix-assisted laser desorption/ionization-time of flight-mass spectrometry), an MS method particularly suited to determining molecular masses of biopolymers and synthetic materials with relative masses up to several hundred kilodaltons, determined that the product contained stoichiometric amounts of the heme starting material, the copper complex, and dioxygen in a 1 1 1 ratio. 

TABLE 7.9 Selected Bond Distances and Angles for Fe -(Oi )-Cn Complexes 

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