Biochemical targets of nitric oxide-induced toxicity

Nitric oxide (NO) has become one of the most intensively studied molecules in recent years. Although its beneficial role has been well established, a large body of adverse effects was also attributed to NO and/or its red-ox derivatives in biological systems. Peroxynitrite (ONO-), a product of reaction between NO and superoxide anion (O2•-) was recognized as a potent pro-oxidant endogenous toxicant. The agent was found to induce DNA and protein oxidative damages leading to increased risk(s) of severe human pathologies including cancer. In this review, the discrete chemical aspects of both nitric oxide and peroxynitrite have been discussed in an attempt to elucidate the major biochemical target(s) of NO-and/or peroxynitrite-induced toxicity.