Detection and Characterization of Singlet Oxygen
Light and oxygen are toxic. Environmental chemicals or natural cell constituents that absorb light (such as porphyrins or flavins) can “sensitize” organisms to damage. Examples in man include photosensitive porphyrias, drug photosensitivity, and photoallergy. Aging of sun-exposed skin, cataract induction, and photocarcinogenesis may be caused by related chemical mechanisms. Damage to organisms caused by light and oxygen in the presence of dyes or pigments is called “photodynamic action”; damage to biological target molecules includes enzyme deactivation (through destruction of specific amino acids, particularly methionine, histidine, and tryptophan), nucleic acid oxidation (primarily guanine), and membrane damage (unsaturated fatty acids and cholesterol are targets). There are many naturally-occurring photodynamic sensitizers that can cause harm to humans, mammals, or plants: for example, porphyrins from blood or chlorophyll, the plant toxin hypericin, the fungal pigment cercosporin, and several polyacetylene derivatives.
KeywordsSinglet Oxygen Photodynamic Action Quench Singlet Oxygen Photosensitize Oxidation Drug Photosensitivity
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Suggestions for Further Reading
- Turro, N.J., 1978, “Modern Molecular Photochemistry,” Benjamin/Cummings, Menlo Park, Ca.Google Scholar
Photo dynamic Action
- Krinsky, N.I., 1983, Biological roles for singlet oxygen, in “Singlet Oxygen,” H.H. Wasserman and R.W. Murray, Eds., Academic Press, New York, 597.Google Scholar
- H.H. Wasserman and R.W. Murray, eds., “Singlet Oxygen,” Academic Press, New York.Google Scholar
Characterization of Reactive Intermediates
- Packer, L., Ed., 1984, Oxygen radicals in biological systems, in Methods in Enzymology, 105:Google Scholar