Fig. 4.

Analysis of modified cysteines of Der p 1 by in-gel digestion, followed by RP-LC-MS/MS, after incubation with GSTpi in the absence or presence of GSH. (A) Summary of peptide spectra number containing unmodified and modified cysteine residues: GSH conjugation, reduced and oxidized. (B) 3D-structure of Der p 1 dimer. Ribbon representation was generated using PyMOL by taking known structure as template (PDB Ref. 3F5V). Cysteine residues are indicated in the structure. Mature enzyme has three disulphide bridges: Cys4-Cys117, Cys31-Cys71, and Cys65-Cys103. The catalytic cysteine residue is Cys34.