Zinc in pigmented cells and structures, interactions and possible roles.

Zinc is a feature trace element of pigment cells and tissues. Organelles, in which melanin is synthesized and stored, i.e. melanosomes, represent a zinc reservoir at the subcellular level. In order to understand function of metals in tissues, cells and their constituents, knowledge is needed on metal interactions with intracellular targets. The possible zinc ligands in pigment cells include melanin, metallothionein, melanotransferrin, B700 and related proteins, ferritin, zinc enzymes and low molecular weight ligands. Areas of a special interest in relation of pigment cells and structures to zinc--such as zinc effect on melanogenesis, zinc excretion and buffering by melanosomes, zinc function in free radical processes as well as zinc role in melanomas--have been reviewed. High level of zinc in pigment cells may indicate a physiological defense against the potential danger of oxidative stress.