[Photo-induced destruction of DOPA-melanin].
Studies of the effect of illumination at different wavelengths revealed a high stability of DOPA-melanin to the visible light. Contrariwise, UV-visible light of high intensity upon prolonged (many hours) illumination caused a significant bleaching of the diluted aqueous solution of the pigment. The absorption spectrum of DOPA-melanin in the UV- and IR-regions did not differ from the initial one; however, the illuminated pigment acquired an ability for fluorescence. Stepwise gel chromatography on Toyopearl-55 and Toyopearl-40 columns resulted in three fractions of photobleached DOPA-melanin which differed in their molecular masses, absorption spectra (UV, IR) and fluorescence. It was concluded that the photoinduced bleaching of DOPA-melanin was mainly due to the pigment depolymerization. A possible mechanism of melanin photodestruction is discussed.
Korzhova
L P
LP
Frolova
E V
EV
Romakov
Iu A
IuA
Kuznetsova
N A
NA
D002850:Chromatography, Gel; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000032:analysis / Q000528:radiation effects; D010777:Photochemistry; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014466:Ultraviolet Rays
D004295:Dihydroxyphenylalanine; C040616:DOPA melanin
Fotoindutsirovannaia destruktsiia DOFA-melanina.