Structure of cysteine persulfide (IMAGE) Kumamoto University Caption Hydrogen sulfide (H<sub>2</sub>S) is attached to the thiol group (-SH) of cysteine. Credit Professor Tomohiro Sawa Usage Restrictions To use this media elsewhere, the authors request a reference to the original work (this release) be included. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.