Melanoma is one of the most lethal and malignant cancers and its incidence is increasing
worldwide, and Japan is not an exception. Although there are numerous therapeutic options …

Protein-bound 3, 4-dihydroxyphenylalanine (DOPA) can be generated in mammalian cells
by both controlled enzymatic pathways, and by uncontrolled radical reactions. Protein …

Different wavelengths of ultraviolet (UV) radiation elicit different responses in the skin. UVA
induces immediate tanning and persistent pigment darkening through oxidation of pre …

A simple and rapid method was developed for the determination of 3, 4-
dihydroxyphenylalanine (dopa) and 5-S-cysteinyl-3, 4-dihydroxyphenylalanine (5-S …

Some amino acids have bioregulatory functions, which far exceed those of precursors for
proteins or of substrates for specific enzymes. Two of these amino acids, L-tyrosine and L …

Background. Urinary excretion of 5‐S‐cysteinyldopa (5‐S‐CD) has been used as a
biochemical marker of melanoma progression. Melanomas produce not only 5‐S‐CD but …

Levodopa (L‐dopa) is the most widely used agent for the symptomatic relief of Parkinson's
disease. There is concern that chronic L‐dopa treatment may be detrimental, with some …

To elucidate the source and physiological significance of plasma 3, 4‐
dihydroxyphenylalanine, the immediate product of the rate‐limiting step in catecholamine …

Melanogenesis, ie, synthesis of melanin and melanosomes, is a “cascade''of event which is
channelled by internal and external regulatory factors. The recognition and selection of this …

Melanin synthesis is a biologic property unique to the melanocyte. It is highly elevated in
malignant melanoma with the production of both eumelanin (brown/black pigment) and …