ABSTRACT
ROS and RNS signaling in the catalysis of heterolytic reactions by protein kinases and other enzymes is one of the most unexpected biological functions of superoxide (O2·−), nitric oxide (NO), and reactive diamagnetic molecules originated from these physiological free radicals (rst of all, hydrogen peroxide and peroxynitrite [ONOO−]). Mechanisms of these catalytic processes will be discussed later (Chapter 7); however, it should be noted here that it was difcult to imagine earlier that free radicals, well-known damaging species, could participate in heterolytic reactions of hydrolysis, etherication, and others. Obviously, the most probable mechanisms of such processes should be electron transfer reactions mediated by ROS and RNS, which will be considered later. In this chapter, we will discuss the experimental ndings of the role of ROS and RNS signaling in reactions catalyzed by protein kinases, protein phosphatases, and phospholipases.
