||Reactive oxygen species (ROS) are natural byproducts of the normal metabolism of oxygen and play important roles in cell signaling and homeostasis. However, during oxidative stress-related states, ROS levels can increase dramatically. The accumulation of ROS results in significant damage to cell structures. The role of oxidative stress in cardiovascular disease, diabetes, osteoporosis, stroke, inflammatory diseases, a number of neurodegenerative diseases and cancer has been well established. The ROS measurement will help to determine how oxidative stress modulates varied intracellular pathways. This ROS Activity Assay Kit uses our unique ROS sensor to quantify mitochondrial ROS in live cells. ROS Deep Red uses a membrane-permeable non-fluorescent ROS sensor, which quickly penetrates mitochondrial membrane and generates very strong deep-red fluorescence signal when it reacts with ROS. The kit is an optimized "mix and read" assay format that is compatible with HTS liquid handling instruments.