Tautomerization of L-dopachrome with decarboxylation to give 5,6-dihydroxyindole (DHI). Also catalyzes the tautomerization of the methyl ester of L-dopachrome and dopamine chrome. May play a role in melanization reactions during late pupal and adult stages. L-dopachrome = 5,6-dihydroxyindole-2-carboxylate Pigment biosynthesis; melanin biosynthesis. Expressed at all stages with highest levels in late-stage pupae and adults. Belongs to the major royal jelly protein family.