Melanin synthesis in mammals is catalysed by at least three enzymic proteins, tyrosinase (monophenol dihydroxyphenylalanine:oxygen oxidoreductase, EC 1.14.18.1) and tyrosinase-related proteins (tyrps) 1 and 2, whose genes map to the albino, brown and slaty loci in mice, respectively. Tyrosinase catalyses the rate-limiting generation of L-dopaquinone from L-tyrosine and is also able to oxidize L...

The aim of the present study is to preliminarily investigate the antimelanogenesis effect of Inonotus obliquus extracts by cell-free mushroom tyrosinase assay. It was found that petroleum ether and n-butanol extracts might contain unknown potential tyrosinase inhibitors, while its ethyl acetate extract might contain some unknown accelerators. Six compounds were isolated and their structures wer...

Vaccination with tumor-associated antigens is a promising approach for cancer immunotherapy. Because the majority of these antigens are normal self antigens, they may require suitable delivery systems to promote their immunogenicity. A recombinant vector based on the modified vaccinia virus Ankara (MVA) was used for expression of human tyrosinase, a melanoma-specific differentiation antigen, an...

Tyrosinase catalyzes the oxidation of phenolic compounds to the corresponding quinines which are subsequently converted to melanin pigments. Loss of the hair shaft melanin is associated with decrease of tyrosinase activity in the bulb of melanocytes. Activators of tyrosinase with stimulatory effects on melanogenesis are beneficial for the preventation of hair whitening and treatment of hypopigm...

and comprises six species. One of these is Amberboa ramosa JAFRI, which is an annual herbaceous plant found in India and Pakistan. The plant has tonic, aperient, febrifuge, deobstruent, cytotoxic, and antibacterial activities. Previously triterpenoids, flavanoids, steroids, and steroidal glycosides have been reported from this species. Here we report the isolation and structure elucidation of l...

Tyrosinase or polyphenol oxidase (EC 1.14.18.1) is the key enzyme in melanin biosynthesis and in the enzymatic browning of fruits and vegetables. The role of tyrosinase in the secondary metabolism of plants still remains unclear, but its implication in betalain biosynthesis has been proposed. Betalains are an important class of water-soluble pigments, characteristic of plants belonging to the o...

Tyrosinase is a glycoprotein responsible for the synthesis of melanin in melanocytes. A large number of mutations have been identified in tyrosinase, with many leading to its misfolding, endoplasmic reticulum (ER) retention, and degradation. Here we describe the folding and maturation of human tyrosinase (TYR) using an in vitro translation system coupled with ER-derived microsomes or with semip...

Essential oils extracted from aromatic plants exhibit important biological activities and have become increasingly important for the development of aromatherapy for complementary and alternative medicine. The essential oil extracted from Cinnamomum cassia Presl (CC-EO) has various functional properties; however, little information is available regarding its anti-tyrosinase and anti-melanogenic ...

We simulated the docking of the tertiary structure of mushroom tyrosinase with our compounds. From the structure-tyrosinase inhibitory activity relationship, it is notable that compounds 4, 8 and 11 showed similar or better activity rates than kojic acid which was used as a positive control. Compounds 17, 21, and 23 among benzene analogs that possess the same substituent showed significantly lo...

We designed high-affinity primers for the mRNA sequence of human tyrosinase to test the value of molecular detection of circulating melanoma cells by reverse transcription-polymerase chain reaction (RT-PCR). The optimization process included in vitro settings and in vivo studies in a xenograft mouse model. We detected tyrosinase expression with at least 40 pg and 1.5 pg of total RNA extracted f...