Kinetic Properties of (+)-Catechin Oxidation by a Basic Peroxidase Isoenzyme from Strawberries

摘要

The ability of a partially-heat stable strawberry (Fragaria X ananassa) peroxidase to oxidize (+)-catechin was studied and its oxidation fol- lowed the accepted model for peroxidase oxidations. Compound I (CoI) and compound II (CoII) were the main intermediates in the catalytic cycle. The reactivity of strawberry peroxidase with H_2O_2 [k_1 = 2.63 μM~-1 s~-1] and with (+)-catechin [k_3 = 0.57 μM~-1 s~-1] suggested that (+)-catechin is an excellent o-diphenol for CoII reduction. The strong cooperativity of this peroxidase isoenzyme indicates its great efficacy in oxidation of (+)-catechin at low H_2O_2 concentrations.