part of carbon-sulfur lyase activity ergothioneine biosynthetic process hercynylcysteine sulfoxide lyase activity (ergothioneine-forming) https://github.com/geneontology/go-ontology/issues/30193 MetaCyc:RXN-14428 RHEA:42688 2014-07-02T15:45:43Z GO:1990411 molecular_function Catalysis of the reaction: hercynylcysteine sulfoxide + 2H+ = ergothioneine + pyruvate + ammonium. mah