[Quantitative determination of phenoloxidase (EC 1.14.18.1). Spectrophotometry measurement of the activity of mushroom and potato tyrosinase].

With dopa as substrat the enzyme were incubated 20 min in 0.1 M phosphate buffer, pH 6.8. After that the activity was detected at wavelengths of 313 and 492 nm using a layer thickness of 10 mm. Employing this conditions higher activities were estimated in the commercial preparates as indicated. The high sensitivity commends this standardized method to use in melanoma research.