Production and characterization of recombinant lignin peroxidase isozyme H2 from Phanerochaete chrysosporium using recombinant baculovirus

Recombinant Phanerochaete chrysosporium lignin peroxidase isozyme H2 (pI 4.4) was produced in insect cells infected with a genetically engineered baculovirus containing a copy of the cDNA clone λML-6. The recombinant enzyme was purified to near homogeneity and is capable of oxidizing veratryl alcohol, iodide, and, to a lesser extent, guaiacol. The K_m of the recombinant enzyme for veratryl alcohol and H₂O₂ is similar to that of the fungal enzyme. The guaiacol oxidation activity or any other activity is not dependent upon Mn²⁺. The purified recombinant peroxidase is glycosylated with N-linked carbohydrate(s). The recombinant lignin peroxidase eluted from an anion exchange resin similar to that of native isozyme H1 rather than H2. However, the pI of the recombinant enzymes is different from both H1 and H2 isozymes. Further characterization of native isozymes H1 and H2 from the fungal cultures revealed identical N-terminus residues. This indicates that isozymes H1 and H2 differ in post-translational modification.