The enzyme was originally described from the yeast Saccharomyces cerevisiae (as EC 18.104.22.168), though it had not been well characterized. It was also incorrectly described from several bacteriophages as a hydrolase (EC 22.214.171.124). Later work has shown the bacteriophage enzyme to be a lyase. The enzyme binds its substrate at the border between two subunits of a trimeric complex in a position that prevents it from interacting with water. Instead, the substrate reacts with itself and splits in two. The product, L-homoserine lactone, spontaneously hydrolyses to L-homoserine.
EC 126.96.36.199 created 2022 (EC 188.8.131.52 created 1965, incorporated 2022, EC 184.108.40.206 created 1972 as EC 220.127.116.11, modified 1976, modified 2018, transferred 2022 to EC 18.104.22.168, incorporated 2022)