1. Screening compounds, Inhibitor control and Blank Control Preparations: Dissolve test inhibitors into proper solvent. Dilute to 5X the desired test concentration with Tyrosinase Assay Buffer before use. Add 20 μl diluted test inhibitors, Inhibitor Control working solution, or Tyrosinase Assay Buffer into wells assigned as test inhibitors (Sample, S), Inhibitor Control (IC), or Tyrosinase Enzyme Control (EC) wells, respectively. Additional wells with serial dilutions of the test inhibitors may be prepared at this time if desired, containing 20 µl in each candidate well. Note: Preferred final solvent concentration should not be more than 5% by volume. If solvent exceeds 5% include a Solvent Control to test the effect of the solvent on enzyme activity.