Determination of a catalytic tyrosine in Trametes cervina lignin peroxidase with chemical modification techniques

Trametes cervina lignin peroxidase (LiP) lacks a catalytic tryptophan strictly conserved in other LiP and versatile peroxidases. It contains tyrosine¹⁸¹ at the potential catalytic site. This protein and the well-characterized Phanerochaete chrysosporium LiP with the catalytic tryptophan¹⁷¹ have been chemically modified: the tryptophan-specific modification with N-bromosuccinimide sufficiently disrupted oxidation of veratryl alcohol by P. chrysosporium LiP, whereas the activity of T. cervina LiP was not affected, suggesting no catalytic tryptophan in T. cervina LiP. On the other hand, the tyrosine-specific modification with tetranitromethane did not affect the activities of P. chrysosporium LiP lacking tyrosine but inactivated T. cervina LiP due to the nitration of tyrosine¹⁸¹. These results strongly suggest that tyrosine¹⁸¹ is at the catalytic site in T. cervina LiP.