NCIt definition : A sulfur-containing uracil. An established antithyroid drug and highly selective inhibitor
of nitric oxide synthase (NOS), thiouracil also covalently binds to dopaquinone, produced
by tyrosinase catalyzed oxidation of tyrosine, thereby selectively accumulating in
de novo-synthesized melanin in overactive melanin-producing cells and providing a
means to localize melanoma cells. (NCI04);