PARTICIPATION OF MN(II) IN THE CATALYSIS OF LACCASE, MANGANESE PEROXIDASE AND LIGNIN PEROXIDASE FROM PHLEBIA-RADIATA

Oxidation capacities of laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP) from Phlebia radiata were compared using non-phenoli c (veratryl alcohol and ABTS) and phenolic (syringaldazine, vanillalac etone and Phenol red) compounds as reducing substrates. The effect of Mn(II) on enzyme reactions was also studied. Highest specific activiti es were recorded with laccase in the oxidation of phenolic compounds o r ABTS and irrespective of Mn(II) concentration. LiP and MnP oxidized all these substrates but only the catalysis of MnP was dependent upon Mn(II). Only LiP clearly oxidized veratryl alcohol. However, Mn(II) in terfered with this reaction by repressing veratraldehyde formation. Th ese results point to multiple participation of manganese ions, either as a reducing (Mn(II)) or oxidizing (Mn(III)) agent in the enzymatic r eactions.