Cilento G, Adam W
Department of Biochemistry, Universidade de São Paulo, Brazil.
Free Radic Biol Med. 1995 Jul;19(1):103-14. doi: 10.1016/0891-5849(95)00002-f.
Biologically/medically important compounds, when metabolized, can generate free radicals from which electrically excited products--often in the triplet state--are generated. Peroxidases are particularly apt to catalyze such processes, which usually entail oxidations by electron transfer. In the latter case, the chemiluminescence may derive from peroxyl and alkoxyl radicals or excited states derived from dioxetanes. Besides peroxidases, prostaglandin-H synthase and lipoxygenase may catalyze the formation of excited carbonyls. The pronounced similarity in the chemical behavior and reactivity of radicals and excited species derives in part from the biradical nature of the latter. Usually in analyzing the biological effects of xenobiotics, only radicals and/or reactive ground state products have been considered. However, in such processes the generation of excited species is possible, which should be tested for by direct and/or sensitized emission or by photochemical transformation.
具有生物学/医学重要性的化合物在代谢时会产生自由基，由此生成电激发产物——通常处于三重态。过氧化物酶尤其易于催化此类过程，这些过程通常涉及通过电子转移进行的氧化反应。在后一种情况下，化学发光可能源自过氧自由基和烷氧自由基或由二氧杂环丁烷衍生的激发态。除了过氧化物酶外，前列腺素-H合酶和脂氧合酶也可能催化激发态羰基的形成。自由基和激发态物种在化学行为和反应性上的显著相似性部分源于后者的双自由基性质。通常在分析外源性物质的生物学效应时，仅考虑自由基和/或活性基态产物。然而，在这些过程中可能会生成激发态物种，对此应通过直接和/或敏化发射或光化学转化进行检测。
