Qualitative Colorimetric Assay of Tyrosinase Substrates and Inhibitors. ∗

Summary

1. A qualitative in vitro colorimetric assay for potato tyrosinase substrates and inhibitors is described. 2. L-tyrosine, tyrosine ethyl ester, and chloracetyl-L-tyro-sine were found to be suitable substrates, and the latter 2 compounds were attacked more rapidly than tyrosine itself. 3. These findings are in agreement with reported manometric studies on the specificity and velocity of plant tyrosinase. 4. The potato tyrosinase system was compared with one employing the enzyme from the Harding-Passey mouse melanoma.