The soluble and insoluble (particle-bound) tyrosinase (EC 1.10.3.1) present in extracts of Harding-Passey, B-16, and Cloudman S-91 mouse melanoma was examined by means of differential solubility, continuous-flow paper electrophoresis and acrylamide-gel electrophoresis. Two soluble tyrosinases (T1 and T2) were found to exist as distinct entities in each type of melanoma examined. The rela tive c...

Phenoloxidases/tyrosinases initiate melanin synthesis in almost all organisms, and are involved in different biological activities such as the colour change of human hair and the browning or blackening of fruit skin etc. In many invertebrates, defence reactions are linked to phenoloxidase activity and/or melanization. Contacts with foreign molecules are able to trigger the prophenoloxidase (pro...

Most of the phenol compounds are toxic and have been considered as hazardous pollutants. Several physicochemical and biological methods are available to detect and monitor the phenol pollutants in water and soil. In the present study, phenol constituents of winery, paper and plastic industrial effluents were successfully detected employing tyrosinase-gold nanoparticles bioconjugate. The synthes...

Tyrosinase has been suggested as a prodrug-converting enzyme for the treatment of melanoma. We hypothesized that tyrosinase expression in transfected nonmelanotic cells can be used in a gene therapy paradigm of prodrug activation. To verify our hypothesis, we used the following tyrosinase variants: (a) a full-length human tyrosinase clone (T); (b) a mutant lacking the COOH-terminal cytoplasmic ...

The enzyme system responsible for Amphibian Kupffer Cell (KC) melanogenesis has not been entirely elucidated. This research demonstrates that the KC melanosomes of Rana esculenta L. possess a tyrosine-hydroxylase (TH) activity, showing that a tyrosinase is the enzyme involved in the melanogenesis. The TH reaction depends on catalytic Dopa as a cofactor and is not affected by catalase or H2O2, s...

ATTEMPTS have been made to classify the phenolases into groups such as the catechol oxidases, tyrosinases, and laccases [Raper, 1928], but the classification is made difficult by the lack of satisfactory methods of characterising the enzymes [Onslow and Robinson, 1928]. The present work was undertaken with the object of testing whether the catechol oxidases of different origin behave similarly ...

BACKGROUND The 3,4-dihydroxy phenyl L-alanine (L-dopa) is a drug of choice for Parkinson's disease, controlling changes in energy metabolism enzymes of the myocardium following neurogenic injury. Aspergillus oryzae is commonly used for L-dopa production; however, potential improvements in ease of handling, growth rate and environmental impact have led to an interest in exploiting alternative ye...