Evidence for a glycidic-lipidic matrix in human neuromelanin, potentially responsible for the enhanced iron sequestering ability of substantia nigra.
The high-resolution solid-state 13C-NMR spectrum of a neuromelanin specimen (from patients dying from nonneurological diseases) is compared with that obtained from enzymatically prepared dopamine-melanin. The main differences between the two spectra suggest the occurrence in neuromelanin of a glycidic/lipidic matrix tightly associated with the melanin macromolecule. Atomic emission spectroscopy revealed high iron content (1.5%) in the neuromelanin specimen, in full agreement with previous reports. These observations support the view that neuromelanin acts as a strong chelating (and insolubilizing) system for iron ions and further suggest that the attack to this compact composite substrate may be an important step to allow the release of iron ions responsible for the increased lipid peroxidation reported in the pathogenesis of Parkinson's disease.
Aime
S
S
Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Università di Torino, Italy.
Fasano
M
M
Bergamasco
B
B
Lopiano
L
L
Valente
G
G
D002247:Carbon Isotopes; D004298:Dopamine / Q000737:chemistry; D004852:Epoxy Compounds / Q000032:analysis*; D006801:Humans; D007501:Iron / Q000378:metabolism*; D015227:Lipid Peroxidation; D008055:Lipids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008543:Melanins / Q000737:chemistry* / Q000378:metabolism*; D008875:Middle Aged; D010300:Parkinson Disease / Q000378:metabolism; D011422:Propionates / Q000032:analysis*; D013378:Substantia Nigra / Q000378:metabolism*
D002247:Carbon Isotopes; D004852:Epoxy Compounds; D008055:Lipids; D008543:Melanins; D011422:Propionates; C014121:neuromelanin; C007869:glycidic acid; D007501:Iron; D004298:Dopamine