PNNL

Abstract

Oxidative modifications of protein cysteines play a crucial role in regulating redox homeostasis, redox signaling, and protein function. One of the modifications involves the oxidation of a cysteine thiol to a sulfinic acid (R-SO2H) which has been considered a marker for oxidative stress and an important activator for certain proteins. Here we report a protocol for the selective formation of sulfinic acids on cysteine residues in a simple 3-step operation under mild conditions: thiol-blocking, oxidation, and reduction. The specificity and efficiency of the method were demonstrated by using both small molecule substrates and a protein model.