Characterization of the three-phase partitioned laccase from Trametes versicolor strain with antiproliferative activity against breast cancer cells.

An extracellular laccase from T. versicolor was 20.4-fold purified by three-phase partitioning with high recovery (245 %) and biochemically characterized in detail for the first time. Its molecular weight was found to be 66.39 kDa. The enzyme showed activity towards the substrates ABTS, 2,6-DMP, guaiacol and hydroquinone. The substrates with the highest catalytic efficiency (k/K) were ABTS and 2,6-DMP. The maximum laccase activity value was reached at 70 °C for all substrates; at 80 °C even an activity of >60 % could be maintained. The optimum pH values were 4.5, 5 and 5.5 for ABTS, 2,6-DMP and guaiacol, respectively. In solutions with pH values of 3.5 to 5, it was active for up to 6 h. Laccase activity was negatively affected by L-cysteine, kojic acid, β-mercaptoethanol, sodium azide and SDS. In contrast, non-ionic detergents showed no significant effects on the enzyme. The enzyme showed activity when exposed to low concentrations (<5 %) of the solvent's methanol, ethanol and DMSO. Among the metal ions, the enzyme showed strong sensitivity to Fe, while Ni and Mn showed increased activity. Biochemical analyses have shown that the laccase enzyme has superior properties compared to its commercial form (such as high temperature and pH stability, high affinity to its substrates and relatively high catalytic efficiency). Its anticancer effect on breast cancer cell lines was also investigated. The results emphasize the potential of pure laccase as an anticancer agent due to its selective lethal effect on breast cancer cells.