RELEASE OF GLUTATHIONE INHIBITION OF MELANIN FORMATION BY ESTRONE

Abstract

Estrone in conc. higher than 0.3 mg. per 20 cc. partially inhibited the formation of melanin in a tyrosine-tyrosinase mixture. The degree of inhibition was dependent on the conc. The pigment or pigments which formed in such mixtures appeared reddish brown in contrast to the jet black pigment formed in mixtures without estrone. The color might be due to a mixture of reduced melanin and a red oxidation product of estrone. Glutathione (1.2 mg. per 20 cc.) completely inhibited the formation of melanin by tyrosinase for a period of 5 hrs. When estrone and glutathione were added in equimolecular quantities (1 mg. estrone and 1.2 mg. glutathione) to a tyrosine-tyrosinase mixture, the estrone released the enzyme from the glutathione inhibition in 1 hr.