SQR oxidizes sulfide to bound persulfide Authored: Stephan, R, 2010-10-24 Edited: Jassal, B, 2011-09-29 Pubmed12832624 Pubmed18494801 Reactome Database ID Release 431614665 Reactome, http://www.reactome.org ReactomeREACT_115885 Reviewed: D'Eustachio, P, 2011-10-13 When SQR is in the oxidized state, it can bind hydrogen sulfide as persulfide to one of its own cysteine residue, the electrons being transferred to ubiquinone. After that the additional sulfur is dioxygenated by another enzyme (ETHE1). The activity of human SQR was deduced from the orthologue in <i>Arenicola marina</i> (Theissen et al. 2003, Hildebrandt & Grieshaber 2008). has a Stoichiometric coefficient of 2 has a Stoichiometric coefficient of 4