Direct over-expression, characterization and H2O2 stability study of active Pleurotus eryngii versatile peroxidase in...

The vpl2 gene, encoding versatile peroxidase (VP) from Pleurotus eryngii, was synthesized with codon optimization and cloned into vector-pET-32a(+) and over-expressed in Escherichia coli BL21(DE3). An active peroxidase fused to the thioredoxin-hexahistidine tag was directly obtained by IPTG induction in the presence of hemin. Most of over-expressed protein was in the soluble form, and was purified on a nickel column with >85 % purity at a yield of 12.5 mg/l. The purified fusion protein, having an Rz value (A(407)/A(280), a measure of hemin content of the peroxidases) of 1.2, oxidized ABTS veratryl alcohol, Mn(2+), and Reactive Black 5. Activity of the enzyme increased after removing the tag. It lost only 5 % of its activity in 6.4 mM H(2)O(2). This is the first report on direct over-expression of active VP in E. coli.