Comprehensive literature investigations revealed that bifloranes are primarily found in animals, plants, and certain microorganisms . Examples include the anti-inflammatory and analgesic pseudopterosin A from corals (Supplementary Figure ), the antimalarial kalihinol A from sponges , and the cytotoxic leubethanol from plants . Despite their significances, biosynthesis studies on the biflorane skeleton are scarce. Kerr 31 demonstrated that elisabethatriene serves as the precursor to pseudopterosins through a method involving radioactivity-guided isolation. This method analyzed the incubation products of a cell-free extract from the coral Pseudopterogorgia elisabetha when combined with 3 H-GGPP. Additionally, Yamada discovered that hydropyrene synthase produces isoelisabethatriene B and isoelisabethatriene with a biflorane backbone as a by-product (Supplementary Figure ). Subsequently, Rinkel conducted extensive labeling experiments to investigate the catalytic mechanism of hydropyrene synthase . Despite these efforts, the labeled products were not isolated, leaving the protein structure and the catalytic key residues unresolved. In addition, Burkhardt identified two diterpenoid synthases (PbTC-1 and HcTC-3) that catalyze the cyclization of GGPP to form elisabethatriene in corals . However, the plants harbor distinct terpene synthases that use nerylneryl diphosphate (NNPP) instead of GGPP as a substrate to form the biflorane scaffolds (Supplementary Figure ) . Despite the identification of several biflorane synthases, further insights into the catalytic mechanisms of the biflorane skeleton, as well as detailed structure and active site analyses of these synthases, remain scarce. The only exception is Rinkel's exploration of the catalytic mechanism of hydropyrene synthase, which includes the production of bifloranes as by-products .