[The phenoloxidase activity in the presence of H2O2, EDTA, and copper (author's transl)].

Investigations performed with cryostat sections of the gut, spleen and lung of the rat have shown, that the substrate of PER H2O2 inhibits the PO activity in dependence of the concentration, and that obvious the PO substrate DOPA is no suitable H2-donator for the PER reaction. Therefore a false positive reaction by the PO proof is not to be expected. Copper sulfat does not influence the PO reaction, but it accelerates melanin formation, which causes an unspecific colouring of the tissue.