Effects of copper on the tyrosinase of liver pigment cells from Rana esculenta L.
1. The liver pigment cells of R. esculenta L. constitute a peculiar pigment cell system of histiocytic nature and contain a tyrosinase-like activity localized in the protein component of melanosomes. 2. The effects of addition and/or removal of Cu on the DOPA-oxidase activity of the system were studied. 3. It was concluded that: (a) this tyrosinase behaves as a Cu-enzyme; (b) Cu could be involved in the regulation of the enzyme activity; and (c) mixtures of apoenzyme and active enzyme coexist in the melanosomes.
Cicero
R
R
Istituto di Biologia Generale, Facoltà di Medicina e Chirurgia dell'Università di Bari, Italy.
Gallone
A
A
Maida
I
I
Pintucci
G
G
D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D008544:Melanocytes / Q000201:enzymology*; D014442:Monophenol Monooxygenase / Q000302:isolation & purification / Q000378:metabolism*; D011893:Rana esculenta
D003300:Copper; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase; D019327:Copper Sulfate