title: Significant enhancement of monooxygenase activity of oxygen carrier protein hemocyanin by urea.
abstract: 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. The oxygenation of phenols by hemocyanin also proceeded catalytically when the reaction was carried out under aerobic conditions.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Chiyuki
authors.initials: C
authors.lastname: Morioka
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Tachi
authors.forename: Shinnichiro
authors.initials: S
authors.lastname: Suzuki
authors.forename: Shinobu
authors.initials: S
authors.lastname: Itoh
mesh_terms: D000818:Animals; D003408:Cresols / Q000737:chemistry; D006433:Hemocyanins / Q000737:chemistry* / Q000378:metabolism*; D016014:Linear Models; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism; D049831:Octopodiformes; D010100:Oxygen / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D014508:Urea / Q000737:chemistry*
chemical_list: D003408:Cresols; C032538:4-cresol; D014508:Urea; D006433:Hemocyanins; D006899:Mixed Function Oxygenases; D010100:Oxygen