Mitigation of the allergenic activity of beta-lactoglobulin by electrolysis

Beta-lactoglobulin (BLG) is the most prominent allergen causing milk allergy and contains disulfide (S-S) bonds that may be responsible for its allergic action. As S-S bonds may be reduced during electrolysis, this study was undertaken to evaluate modulation of the allergic action of BLG after electrolysis. A current of 85 mA/cm(2) was applied, and the allergic action was evaluated by means of competitive CAP-FEIA inhibition tests and skin prick tests (SPT). Modification of BLG was examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). Although the number of total free sulfhydryl (SH) groups of BLG did not differ between the cathode and anode sides, BLG on the cathode side showed 54% lower inhibition than untreated BLG in the competitive CAP-FEIA inhibition tests, and reduced wheal reactions, by 71%, in the SPT compared with those with untreated BLG. The SPT results with BLG on the anode side did not differ significantly from those with untreated BLG. The MALDI-ToF-MS results for the dimer of untreated BLG or BLG on the anode side showed two distinct peptide fragments (residues (41)V-(60)K and (149)L-(162)I) but, on the contrary, the dimer of BLG on the cathode side did not give these fragments, this being similar to in the case of the monomer of BLG. The allergic action of BLG was markedly mitigated during electrolysis on the cathode side, a dimer of BLG with a different mass spectrometric pattern from that of the dimer of untreated BLG being simultaneously formed.