The photoreactive free radical in eumelanin
#MMPMID29600273
Mostert AB
; Rienecker SB
; Noble C
; Hanson GR
; Meredith P
Sci Adv
2018[Mar]; 4
(3
): eaaq1293
PMID29600273
show ga
Melanin is the primary photoprotecting pigment in humans as well as being
implicated in the development of deadly melanoma. The material also conducts
electricity and has thus become a bioelectronic model for proton-to-electron
transduction. Central to these phenomena are its spin properties-notably two
linked species derived from carbon-centered and semiquinone radicals. Using a
novel in situ photoinduced electron paramagnetic resonance technique with
simultaneous electrical measurements, we have elucidated for the first time the
distinct photoreactivity of the two different radical species. We find that the
production of the semiquinone is light- and water-driven, explaining the
electrical properties and revealing biologically relevant photoreactivity.
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