Changes of lipo-melanosome membrane leakage versus pH, charge and composition.
Liposome models of melanosomes (lipo-melanosomes) were used to investigate how phospholipid composition, charge and medium pH may affect the lipo-melanosome membrane permeability to active oxygen species or melanin synthesis intermediaries. Active oxygen accumulated only at pH 6.4 and was polarographically monitored using superoxide dismutase and/or catalase. Cholesterol appears to increase the O2- accumulation at pH 6.4 while incorporation of positive phospholipids within lipo-melanosomes results in the loss of latency with respect to tyrosinase substrate and intermediates of melanin synthesis.
Miranda
M
M
Department of Cell Biology and Physiology, University of L'Aquila, Italy.
Amicarelli
F
F
Bonfigli
A
A
Botti
D
D
Zarivi
O
O
Poma
A
A
D002374:Catalase / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010539:Permeability; D010743:Phospholipids / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
D008081:Liposomes; D008563:Membrane Lipids; D010743:Phospholipids; D004295:Dihydroxyphenylalanine; D002784:Cholesterol; D002374:Catalase; D014442:Monophenol Monooxygenase; D013482:Superoxide Dismutase; D005978:Glutathione; D010100:Oxygen