ABSTRACT
Aerobic organisms require machineries that eliminate reactive oxygen species (ROS) generated by respiration as well as many other normal cellular processes. Although ROS are generally considered to be toxic to cellular materials, increasing evidence suggests that ROS may also function as a second messenger. To protect cellular components against ROS and to modulate the ROS-mediated signaling mechanisms, the in tracellular role of antioxidant enzymes must be studied along with many other aspects. Here we summarize a novel family of antioxidant en zymes and discuss their putative role as modulators of signal transduc tion.
