Regulation of the cytosolic and melanosome-bound tyrosinase activities in Harding-Passey mouse melanoma.
Mouse melanoma tyrosinases exist in the cytoplasm of melanocytes and also in a particulate form, bound to melanosomes. The cytosolic isoenzyme activity is not expressed in the melanocytes in vivo. One of the mechanisms for the activity regulation is the existence of a soluble inhibitor. This inhibition is non-competitive with regard to L-dopa. Particulate tyrosinase can be solubilized from the melanosome by several agents, Brij 35 and Triton X-100 being the most effective ones. Melanin accumulation in the organelle produces a competitive inhibition of the activity.
D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000201:enzymology; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D007700:Kinetics; D008544:Melanocytes / Q000201:enzymology* / Q000648:ultrastructure; D008545:Melanoma / Q000201:enzymology* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D012995:Solubility
D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase; D005969:Glutamate Dehydrogenase