PDI A3 redox status. The redox status of PDI A3 was determined by sequential alkylation with NEM and AMS, SDS-PAGE and Western blotting with mouse anti-PDI A3 antibody. Protein bands were revealed by ECL assay using peroxidase-conjugate anti-mouse antibody and analyzed with a Kodak Image station 2400R equipped with a CCD. Lane 1: control, lane 2: UVB-irradiated NHEK. Upper band: oxidized form; lower band: reduced form.