Common Oxygen Binding Site in Hemocyanins from Arthropods and Mollusks. Evidence from Raman Spectroscopy and Normal Coordinate Analysis

Reversible Dioxygen Binding and Phenol Oxygenation in a Tyrosinase Model System

“…[16] Also typical for this binding geometry are the peaks at 256, 283, and 314 cm À1 , which do not shift upon 18 O 2 substitution (Figure 2A); in resonance Raman spectra of hemocyanin these features have been assigned to CuÀ(Ligand)N stretching vibrations. [17] An alternative assignment of the peak at 283 cm À1 to the symmetric Cu 2 O 2 core stretch, which primarily involves copper motion, has been suggested. [16b] The dioxygen binding process undergone by [Cu 2 (L-66)] 2 occurs in a single observable step; no evidence was found for an intermediate mononuclear copper(ii)-superoxide species.…”

Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase

“…They are not equivalent and are likely to play a different role in biological function. The Cu A copper center seems to be more accessible to the solvent in the binuclear site controls the reactivity of the site and whereas the second copper center (Cu B ) plays a complex role in controlling the local conformation and electrostatic effects in the oxygen cycle [36]. It is proposed, that there is a physical difference in the docking of mono-and o-diphenols to the tyrosinase active site and that this difference would be an essential determinant for the course of the catalytic cycle.…”

Probing metal-mediated O2 activation in chemical and biological systems

“…Using two different assignments of stretching frequencies for the Cu 2 O 2 core, we estimate 18 O EIEs of 1.017 and 1.021, in excellent agreement with the experimental result for oxyHc. Calculations performed using stretching frequencies from a normal mode analysis of the protein [17] predict an 18 O EIE of ∼1.023.…”