Oxygen carriers, binding hemocyanin

Hemocyanine and tyrosinase are of this type, Hemocyanine is the oxygen carrier in molluscs and arthropods. Two Cu ions are involved in a subunit and bind one O2. A deoxy structure of a lobster hemocyanine from Panulitrus interruptus has been reported [43] for which both the Cu are monovalent. Three His coordinate to each Cu, and two Cu and four His are located in the same plane (Fig. 2-23). The two copper ions are not equivalent and no bridging ligand exist between them. Tyrosinase oxidizes phenols to orthoquinones. O2 is coordinated between two Cu ions as a p-peroxo structure. 

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