LIGAND DISPLACEMENT-REACTIONS OF OXYHEMOCYANIN - COMPARISON OF REACTIVITIES OF ARTHROPODS AND MOLLUSKS

The ligand displacement reactions of oxyhemocyanin have been compared over a series of arthropods and molluscs. The arthropods (with the exception of Limulus) are found to be more reactive than the molluscs, (kcancer = .04 hr-1, kbusycon = .002 hr-1, klimulus ≪ 10-4hr-1 N3- reactions). Correlation of the spectral properties of the oxy sites require these to be extremely similar with small differences being associated with shifts in the dd transition energies. The met produced by ligand displacement contains variable amounts of EPR detectable, group 2 exogenous ligand damaged sites (arthropods 25-35%, molluscs 3-9%, Limulus <1%). A parallel (arthropod > mollusc ∼ Limulus ∼ 0) group 2 ligand damaged site is also reported for the half met derivatives. © 1979.