Reactions of superoxide dismutases with HS−/H2S and superoxide radical anion: An in vitro EPR study

• Published in: Nitric oxide 2015-12, Vol.51, p.19-23
• Main Authors: Bolić, Bojana, Mijušković, Ana, Popović-Bijelić, Ana, Nikolić-Kokić, Aleksandra, Spasić, Snežana, Blagojević, Duško, Spasić, Mihajlo B., Spasojević, Ivan
• Format: Article
• Language: English
• Subjects: Copper; Electron Spin Resonance Spectroscopy; EPR; H2S; Hydrogen Sulfide - chemistry; Iron; Manganese; Superoxide dismutase; Superoxide Dismutase - chemistry; Superoxide Dismutase - metabolism; Superoxides - chemistry
• ISSN: 1089-8603; 1089-8611
• DOI: 10.1016/j.niox.2015.09.008

Interactions of hydrogen sulfide (HS−/H2S), a reducing signaling species, with superoxide dimutases (SOD) are poorly understood. We applied low-T EPR spectroscopy to examine the effects of HS−/H2S and superoxide radical anion (O2·−) on metallocenters of FeSOD, MnSOD, and CuZnSOD. HS−/H2S did not affect FeSOD, whereas active centers of MnSOD and CuZnSOD were open to this agent. Cu2+ was reduced to Cu1+, while manganese appears to be released from MnSOD active center. Untreated and O2·− treated FeSOD and MnSOD predominantly show 5 d-electron systems, i.e. Fe3+ and Mn2+. Our study provides new details on the mechanisms of (patho)physiological effects of HS−/H2S. •FeSOD from E. coli and P. leiognathi are resistant to HS−/H2S-induced reduction.•HS−/H2S appears to provoke a release of manganese from MnSOD.•HS−/H2S reduced Cu2+ to Cu1+ in CuZnSOD.•5 d-electron systems predominate in MnSOD and FeSOD.