P57  Lipofuscin and carotenoids

From: Bobby Redmond (redmond@helix.mgh.harvard.edu)
Date: 12/12/97
Time: 7:34:43 PM
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Dear George et al.,

I have a couple of questions about your poster.

(1) I didn't quite understand the nature of the reaction you are proposing for the delayed formation of carotenoid radical cation on reaction of CCl3OO• with beta carotene. (Scheme 1). Could you elaborate on this mechanism? It would appear that the loss of adduct in figure 4 does not correlate with the growth of the radical cation of the carotenoid. There also appears tobe a large shift in the peak assigned to the radical cation from 950 to around 1000 nm as a result of the growth. It looks like two separate species are present, rather than two rates for production of the same radical cation species. Is the "adduct" absorption seen for the benzophenone ketyl peroxyl radical where no electron transfer is proposed? Is there any work in the literature regarding hydrogen abstraction from carotenoids? (2) Any idea as to the nature of the two radical species observed on flash photolysis of lipofuscin in methanol?



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