Systematic screening of reactive cysteine proteomes.

Redox signalling constitutes a topic within the field of cellular signal transduction which is attracting increasing interest. A major challenge is to identify the components of redox signalling pathways. Proteins containing cysteines that may reversibly form disulphides are principal candidates as transmitters of redox signals. Thioredoxins are small proteins containing a highly reactive dithiol. Here we present a simple procedure to isolate and separate proteins that contain redox active cysteines using a site-directed, histidine-tagged mutant of thioredoxin, which forms stable mixed disulphides with its targets.