Epoxide hydrolase responsible for the double epoxide-opening cyclization of bisepoxyprelasalocid A to form lasalocid A, a polyether antibiotic. In vitro, accepts various substrate analogs differing in the left segment of lasalocid and epoxide stereochemistry to afford products with excellent regioselectivity. Consists of two highly homologous domains, oriented in a head-to-tail fashion, that catalyze epoxide-opening cascades independently in lasalocid biosynthesis. The N-terminal domain (Lsd19A) recognizes the internal C18-C19 epoxide of the substrate and catalyzes energetically favored 5-exo cyclization, while the C-terminal domain (Lsd19B) recognizes the internal C22-C23 epoxide of the substrate and predominantly catalyzes energetically disfavored 6-endo cyclization. Cells lacking this gene do not produce lasalocid, they only produce iso-lasalocid.