J. Limson et al., THE INTERACTION OF MELATONIN AND ITS PRECURSORS WITH ALUMINUM, CADMIUM, COPPER, IRON, LEAD, AND ZINC - AN ADSORPTIVE VOLTAMMETRIC STUDY, Journal of pineal research, 24(1), 1998, pp. 15-21
Melatonin, a pineal secretory product, and its precursors, tryptophan
and serotonin, were examined for their metal binding affinities for bo
th essential and toxic metals: aluminium, cadmium, copper, iron, lead,
and zinc. An electrochemical technique, adsorptive stripping voltamme
try, showed the varying abilities of melatonin and its precursors to b
ind the metals in situ. The results show that the following metal comp
lexes were formed: aluminium with melatonin, tryptophan, and serotonin
; cadmium with melatonin and tryptophan; copper with melatonin and ser
otonin; iron(III) with melatonin and serotonin; lead with melatonin, t
ryptophan, and serotonin; and zinc with melatonin and tryptophan. Iron
(II) showed the formation of an in situ complex with tryptophan only.
These studies suggest a further role for melatonin in the reduction of
free radical generation and metal detoxification, and they may explai
n the accumulation of aluminium in Alzheimer's disease.