Keywords: DMF; dimethylformamide; Em; met-tyrosinase; Ed; deoxy-tyrosinase; Eox; oxy-tyrosinase; EmD; met-tyrosinase/l-dopa complex; EoxD; oxy-tyrosinase/l-dopa complex; EmM; met-tyrosinase/l-tyrosine complex; EoxM; oxy-tyrosinase/l-tyrosine complex; D; o-diphenol;