The oligomeric proanthocyanidins (OPCs) from grape seeds are expected to be novel and potent anti-oxidants that more effectively protect skin cells against oxidative stress. UV-induced oxidative stress is considered to promote melanogenesis and serious skin damage. However, the effect of OPCs on UV-induced melanogenesis is still unknown. To investigate the role of OPCs on melanogenesis of human...

The expression of cell-specialization genes is likely to be changing in tumor cells as their differentiation declines. Functional changes in these genes might yield unusual peptide epitopes with anti-tumor potential and could occur without modification in the DNA sequence of the gene. Melanomas undergo a characteristic decline in melanization that may reflect altered contributions of key melano...

Because of its known heterogeneity, the analysis of antigen expression is crucial prior to the initiation of antigen-specific immunotherapy for melanoma. The melanoma differentiation antigens gp100, MART-1 and tyrosinase are involved in a common pathway of melanin synthesis. Peptides derived from these melanoma differentiation antigens are used in the immunotherapy of melanoma and antibodies re...

Patients with Hermansky-Pudlak syndrome type 2 (HPS-2) have mutations in the beta 3A subunit of adaptor complex-3 (AP-3) and functional deficiency of this complex. AP-3 serves as a coat protein in the formation of new vesicles, including, apparently, the platelet's dense body and the melanocyte's melanosome. We used HPS-2 melanocytes in culture to determine the role of AP-3 in the trafficking o...

The authors designed and synthesized 17 (2-substituted phenyl-1,3-dithiolan-4-yl) methanol (PDTM) derivatives to find a new chemical scaffold, showing excellent tyrosinase-inhibitory activity. Their tyrosinase-inhibitory activities were evaluated against mushroom tyrosinase at 50 μM, and five of the PDTM derivatives (PDTM3, PDTM7-PDTM9, and PDTM13) were found to inhibit mushroom tyrosinase more...

experimental autoimmune vitiligo was induced by the intradermal injection of the purified mushroom tyrosinase emulsified in complete freund’s adjuvant (cfa) in female c57bl/6 mice. the onset of vitiligo was characterized by hair hypopigmentation and total melanocyte depletion in the basal layer of the epidermis. oral administration of semipurified mushroom tyrosinase prevented experimental auto...

BACKGROUND The most widely accepted criteria for the evaluation of prognosis of malignant melanoma are histopathologic and clinical presentation. No currently available laboratory tests provide additional prognostic information. It has recently been suggested that reverse transcription and polymerase chain reaction (RT-PCR)-based detection of tyrosinase messenger RNA (mRNA) in peripheral blood ...

Tyrosinase, the enzyme that controls the synthesis of melanin, is a unique product of melanocytes. Normal and malignant human melanocytes grown in culture were used to study the factors that regulate the expression of tyrosinase. Immunoprecipitation experiments showed that newly synthesized tyrosinase appeared as a protein with an apparent molecular weight of 70,000 that was processed to a prot...

Pigmentation of the skin, hair and eyes is regulated by tyrosinase, the critical rate-limiting enzyme in melanin synthesis by melanocytes. Tyrosinase is degraded endogenously, at least in part, by the ubiquitin proteasome system (UPS). Several types of inherited hypopigmentary diseases, such as oculocutaneous albinism and Hermansky-Pudlak syndrome, involve the aberrant processing and/or traffic...

Tyrosinase was found to catalyze the oxidation of phenylhydrazine to phenol in a reaction that did not resemble those typically performed by tyrosinase. The kinetics of this reaction was investigated by measuring the initial velocity of the formation of phenol (25 °C). The values of k cat and K M for the oxidation of phenylhydrazine were obtained as 11.0 s(-1) and 0.30 mM, respectively. The gen...