Kate Carroll, PhD and colleagues at the University of Michigan Life Sciences Institute are reporting the development of a new way to identify proteins affected by a key chemical process important in aging and disease. Scientists know that the excess build-up of highly-reactive oxygen-containing molecules in cells—some of which are the so-called free radicals often blamed for disease—can contribute to aging and possibly to disorders such as cancer and Alzheimer’s. It is also believed that a diet rich in antioxidants, abundant in fruits and vegetables, may help deter this cell-damaging process by blocking the accumulation of these molecules, called reactive oxygen species (ROS). But until now scientists didn’t have the exact means to study the effects of these molecules in detail. The researchers developed a new molecule called DAz-2, which they say functions like a tiny GPS device for quickly finding specific proteins affected by ROS. The molecules do this by chemically "tagging" sulfenic acid. Formed in cells, sulfenic acid indicates that a protein has undergone a type of reaction called oxidation and caused by ROS. In lab studies using cultured cells, the scientists identified more than 190 proteins that undergo this reaction. The study may lead to better strategies for fighting the wide range of diseases that involve these excessive oxidation reactions, say the researchers whose study is due to be published in the September 18 issue of ACS Chemical Biology.