GSTM1 and heart failure: Correspondingly, the levels of S-nitrosylation, the key protein posttranslational modifications maintaining Ca2+ homeostasis and heart rhythm during heart failure [18, 19], were also significantly decreased in AC-sensitive mice, implying that AC could bind to cf-Hb and effectively scavenge NO to induce cell death and fatal arrhythmia (Fig. 6f).