Monooxygenase activity of Octopus vulgaris hemocyanin.

Octopus vulgaris hemocyanin ( Ov-Hc) and one of its minimal functional units ( Ov-g) have been purified, and their spectroscopic features and monooxygenase (phenolase) activity have been examined in detail. The oxy forms of both Ov-Hc and Ov-g are stable in 0.5 M borate buffer (pH 9.

Significant enhancement of monooxygenase activity of oxygen carrier protein hemocyanin by urea.

Oxygenation of a series of p-substituted phenols to the corresponding catechols (phenolase activity) by the (mu-eta2:eta2-peroxo)dicopper(II) species of Octopus hemocyanin has been directly examined for the first time by using a UV-vis spectroscopic method in a 0.5 M borate buffer solution containing 8 M urea under anaerobic conditions. Preliminary kinetic studies have indicated that the reaction involves an electrophilic aromatic substitution mechanism as in the case of phenolase reaction of tyrosinase.

Kinetic evaluation of catalase and peroxygenase activities of tyrosinase.

Tyrosinase is a copper monooxygenase containing a coupled dinuclear copper active site (type-3 copper), which catalyzes oxygenation of phenols (phenolase activity) as well as dehydrogenation of catechols (catecholase activity) using O(2) as the oxidant. In this study, catalase activity (conversion of H(2)O(2) to (1/2)O(2) and H(2)O) and peroxygenase activity (H(2)O(2)-dependent oxygenation of substrates) of mushroom tyrosinase have been examined kinetically by using amperometric O(2) and H(2)O(2) sensors. The catalase activity has been examined by monitoring the initial rate of O(2) production from H(2)O(2) in the presence of a catalytic amount of tyrosinase in 0.