Role of Transition Metal Ions in Generation of Oxygen Species and Their Interconversion

Abstract

Of the oxygen free radicals which could potentially be involved in the generation of singlet oxygen, HO^·, $O_2^{\overline . }$ and ROO^· (i. e the three which are involved in excess in biological systems) seem to be the most likely candidates. Many of the oxygen species such as $O_2^{\overline . }$, HO^·, O, O₃ and ¹O₂ are always present in a cell since they are involved by exposure to sunlight, the earth’s natural background of high energy radiation and by a normal physiological mechanism. The autoxidation of industrially important chemicals and the oxidation of several compounds in the atmosphere are also efficient sources of these species.