part of monooxygenase activity oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen gamma-glutamyl hercynylcysteine sulfoxide synthase activity https://github.com/geneontology/go-ontology/issues/11163 https://github.com/geneontology/go-ontology/issues/30193 gamma-glutamyl hercynylcysteine sulfoxide synthase GO:0044875 RHEA:42672 jl EC:1.14.99.50 2014-12-15T11:44:54Z molecular_function gamma-glutamyl hercynylcysteine S-oxide synthase Catalysis of the reaction: gamma-glutamyl cysteine + hercynine + O2 = gamma-glutamyl-hercynyl cysteine sulfoxide + H2O. ergothioneine biosynthetic process