Fig. 5. Reaction of H₂S with sulfenic acids and not with disulfides could be a mechanism for intracellular persulfidation. (A and B) Incubation of SH-SY5Y neuroblastoma cells with 0.5 mM diamide (30 min) does not increase intracellular persulfidation, while the incubation with H₂O₂ (100 μM, 30 min) leads to a higher intracellular persulfide content (A). Treatment with 100 μM Na₂S (1 h) was used as a positive control. At least 5 images were recorded from each experiment performed in triplicate. (B) Semi-quantification of 40 cells was performed using ImageJ software. Data represent mean ± S.E.M, *p < 0.01.