Biological Implications of Lesions Introduced into DNA by Singlet Oxygen

Abstract

The characterization of the interactions between endogenously or exogenously generated singlet oxygen (¹O₂) and biological systems is receiving increasing attention. An impressive body of knowledge has accumulated which points to the fact that this relatively stable species of molecular oxygen may have specific functions in many biological processes (Krinsky, 1979; Badwey and Karnovsky, 1980; Naqui et al 1986). A number of reactions are capable of generating ¹O₂ under conditions that may be relevant in vivo. These reactions have recently been reviewed by Klebanoff (1980) and among them, it seems that production as a consequence of enzymatic reactions are key steps in metabolism. Examples are given by the metabolism of hydroperoxides by cytochrome PA50 (Cadenas et al., 1983a), the prostaglandiendoperoxyde synthetase reaction (Cadenas et al., 1983b) and the halide mediated hydrogen peroxide decomposition by lactoperoxydase, chloroperoxydase and myeloperoxydase (Kanofsky, 1983). In 1972, Allen et al. have observed that phagocytizing human granulocytes displayed a chemiluminescence during phagocytosis and suggested that this phenomenon reflected the generation of singlet oxygen. They proposed that this species may function as a bactericidal agent.

to whom correspondence should be addressed. Abbreviation: ¹O₂= singlet oxugen; M13 mp19 RF DNA: doublestrand DNA from M13 mp19