Blue copper oxidases evolution

Laccase, 36 318, 329, 40 122 see also Blue copper oxidases amino-acid sequences, 40 141 anaerobic reduction, 40 158-160 biological function, 40 124 electrochemistry, 36 360 fungal, 40 145-152 evolution, 40 153-154 inhibition, 40 162 kinetic properties, 40 157-162 molecular and spectroscopic properties, 40 125-126... 

The evolution of blue oxidases from the small blue proteins clearly shows the transition from protein to enzyme, a result of the development of new and the recombination of existing copper centers. That these copper centers are essential for the enzymes function is demonstrated by the fact that related proteins which have lost their copper centers no longer show enzymatic properties. Only the surface structures of these proteins, i. e., the coagulation factors CF5 and CF8 as well as the pollen antigen Ra3, are required for their function. The evolution of this class of proteins (small blue proteins, pollen antigens, blue oxidases, and coagulation factors) is clearly a result of the evolution of their copperbinding centers. 

Assuming that the linkage between the copper sites in the blue oxidases has been optimized by evolution, the following pertinent questions arise (1) Is the intramolecular ET rate in AO controlled during the multielectron reduction and oxidation (2) Does the rate of intramolecular ET depend on the number of electron equivalents taken up by the molecules (3) Does the rate of ET relate to the conformational changes that were resolved by the structural studies (4) Finally, how can the turnover number of the enzyme, determined under steady state conditions (12,000-14,000 s ), be considerably faster than the above rate of intramolecular ET Since AO molecules reduced to different degrees (from... 

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