Penetrability of White Rot-Degraded Pine Wood by the Lignin Peroxidase of Phanerochaete chrysosporium.

The penetration of enzymes into wood cell walls during white rot decay is an open question. A postembedding immunoelectron microscopic technique was the method of choice to answer that question. Infiltration of pine wood specimens with a concentrated culture filtrate greatly improved the labeling density and, thereby, reproducibility. Characterization of the concentrated culture filtrate by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting) revealed three closely spaced proteins of molecular weights about 42,000 showing immunoreactivity against anti-lignin peroxidase serum. It was shown by immunogold labeling that lignin peroxidase of Phanerochaete chrysosporium is located on the surface of the wood cell wall or within areas of heavy attack. It did not diffuse into undecayed parts of the cell wall. The reasons for preventing lignin peroxidase from penetrating wood cell walls during white rot decay are discussed.