Abstract: We have generated one possible active site structure of Oxyhemocyanin (Oxy-Hc) and two possible active site structures of Oxytyrosinase (Oxy-Ty) using the EHMOmethod. Oxy-Hc active site has a plane configuration, while Oxy-Ty has boat configuration. When there exist water molecules, two water molecules are connected with the Oxy-Ty active site weakly. Calculations for the reactions of Oxy-Hc and Oxy-Ty (the water-off) with phenol demonstrate that the former reaction is thermodynamically forbidden, while the latter Is realizable.

Key words: Oxyhemocyanin, Oxytyrosinase, EHMO calculation, Structure and reactivities, Binuclear copper active site