Catalysis and inactivation of tyrosinase in its action on o-diphenols, o-aminophenols and o-phenylendiamines: Potential use in industrial applications

摘要: Abstract A study of the diphenolase, o-aminophenol oxidase, and aromatic o-diamine oxidase activities tyrosinase carried out by measuring catalysis suicide inactivation kinetics provides following information: catalytic constant, k cat S , Michaelis K M maximum apparent λ max partition ratio “r” between pathway or number turnovers made one mol enzyme before its inactivation. Analysis these data, taking into account chemical shifts carbon atom supporting hydroxyl amino group, (δ) σ p + enables a mechanism to be proposed for transformation o-diphenols, o-aminophenols o-phenylendiamines their products (o-quinones, o-quinoneimine o-diimine), and, at same time, The reaction constants in representations log X / H vs. according Hammett's equation three types substrate (o-diphenols, o-phenylendiamines) confirm that is similar (simultaneous oxidation/reduction process on two copper atoms). dependence reflects lower constant (in absolute value), which might indicate different molecules, but from previous mechanism, only involves atom. We also discuss compare it with those described other authors. Knowledge quantification catalysis/inactivation interest optimizing applications such as wastewater treatment.