Kinetic evaluation of phenolase activity of tyrosinase using simplified catalytic reaction system.
A very simple tyrosinase reaction system has been developed using borate anion as a trapping agent of catechols and hydroxylamine as an external reductant to evaluate the phenolase activity without the interference of catecholase activity. Reactivities of variously para-substituted phenols in this system were compared directly to those of the phenols in the model reactions, demonstrating that the enzymatic oxygenation reaction of phenols proceeds via the same mechanism as the model reaction, that is, electrophilic aromatic substitution mechanism.
Department of Chemistry, Graduate School of Science, Osaka City University 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Shin-ichi
S
Yamazaki
Shinobu
S
Itoh
D001881:Borates / Q000737:chemistry / Q000378:metabolism; D002384:Catalysis; D002396:Catechols / Q000737:chemistry / Q000378:metabolism; D019811:Hydroxylamine / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000737:chemistry* / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D010636:Phenols / Q000737:chemistry* / Q000378:metabolism*
D001881:Borates; D002396:Catechols; D010636:Phenols; D019811:Hydroxylamine; D014442:Monophenol Monooxygenase; D010100:Oxygen