A protein from Pleurotus eryngii var. tuoliensis C.J. Mou with strong removal activity against the natural steroid hormone, estriol: Purification, characterization, and identification as a laccase

A protein with strong removal activity against the natural estrogen estriol was purified from a culture supernatant of Pleurotus eryngii var. tuoliensis C.J. Mou. The protein was characterized as a laccase and had a molecular mass of 60 kDa on SDS-PAGE. The enzyme was most active at pH 7.0 and 50 °C. The partial N-terminal amino acid sequence of the enzyme showed homology with laccases from mushrooms, such as Pleurotus ostreatus, Coriolus versicolor (current name: Trametes versicolor), Pycnoporus cinnabarinus, and P. eryngii. A recombinant yeast assay confirmed that laccase treatment was very efficient for removing the estrogenic activity of steroid estrogens. Our results suggest that the enzyme may be applicable as a potential factor for removing natural steroid hormones.