Figure 2. GFE-EA inhibits tyrosinase activity and attenuates the protein level of tyrosinase in B16-F10 melanoma cells.

(a) For assays of tyrosinase activity, 50 μg of total protein from B16-F10 melanoma cells was incubated with 2 mM L-DOPA, and the level of dopachrome was determined by a photometric method as described in Material and Methods and expressed as percentage of control. (b) Whole cell lysates, treated with 100–200 ppm of GFE-EA for 48 hours, were analyzed by western blotting with antibody against tyrosinase. Equal protein loading was confirmed by antibody against β-actin (full-length gels and blots are presented in Supplementary Figure S2).