Updated project metadata. Reactive oxygen species (ROS) serve as intracellular signaling molecules; however, in excess ROS molecules are damaging to biomacromolecules such as DNA, lipids, and proteins. The excess accumulation of ROS leads to oxidative stress, disrupting redox homeostasis in the cell and has been linked with aging and neurodegenerative disease. The eye is particularly vulnerable to oxidative stress due to the tissue’s high energy demand and generation of ROS by products. In proteins, the thiol group on cysteine residues is susceptible to oxidation. Cysteine residues have multiple oxidation states that can be classified into two categories—reversible and irreversible. Irreversible oxidation states include sulfinic and sulfonic acids, which may alter or impair the activity of the protein depending on the position of the cysteine residue. In contrast, reversible oxidation states include sulfenic acid or inter- and intramolecular disulfides, and can often function as redox sensors in the cell. Here, we sought to evaluate how increasing amounts of oxidative stress alters the redox proteome landscape in Drosophila. To characterize the redox proteome, we developed an iodoTMT-multiplex isolation, labeling, and enrichment method to identify cysteine availability and potential oxidation in both S2 cells and w1118 fly eyes. To do this, we exposed S2 cells to 20mM H2O2 relative to control (untreated), and w1118 flies to prolonged blue light versus an untreated control, followed by redox proteome profiling with iodoTMT-sixplex reagents.