Sqor, which catalyzes the first step in sulfide oxidation, can use various substrates as sulfur acceptors, including glutathione and sulfite; however, glutathione is likely the most used. Tst1, a putative thiosulfate:glutathione sulfurtransferase, may contribute to the production of S-sulfanylglutathione (GSSH) from thiosulfate; however, as there is no experimental evidence, Tst1 is not included in the gene list. Dic2, Dic3 and Dic4 are paralogs of Dic1. Dic2, Dic3 and Dic4 are specifically expressed in the testis. Dic4 appears to lack transport activity and Dic2 lacks functional information. Therefore, Dic2, Dic3 and Dic4 are not included in the gene list.