Co-Authors:
Carmichael, A.J., Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20205, United States
Mossoba, M.M., Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20205, United States
Riesz, P., Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20205, United States
Rosenthal, I., Department of Food Technology, A.R.O. Volcani Center, Bet Dagan 50250, Israel
Abstract:
The light-induced reactions between synthetic food colors and peptides has been investigated by spin trapping and electron spin resonance spectroscopy. It was found that the two certified food color additives of the triphenylmethane type, FD&C Blue No. 1 and FD&C Green No. 3, were able to photosensitize the decarboxylation of di- and tripeptides when the mixture was irradiated with light that was exclusively absorbed by the dye. The decarboxylation radicals were spin trapped by 2-methyl-2-nitrosopropane (MNP) and identified by electron spin resonance (ESR). The other four synthetic dyes tested, FD&C Red No. 3, FD&C Red No. 40, FD&C Yellow No. 5, and FD&C Yellow No. 6, were not able to sensitize this reaction. A mechanism based on an electron transfer from the carboxyl end of the peptide to the photoexcited dye is suggested for this reaction. © 1984 American Chemical Society.