Involved in the biosynthesis of ent-kaurene diterpenoids natural products and in the production of gibberellins phytohormones (PubMed:17456599, PubMed:9536043). Catalyzes the conversion of ent-copalyl diphosphate to the gibberellin precursor ent-kaur-16-ene (PubMed:17456599, PubMed:9536043). ent-copalyl diphosphate = diphosphate + ent-kaur-16-ene Binds 3 Mg(2+) ions per subunit. kcat is 0.06 sec(-1) with ent-copalyl diphosphate as substrate. Plant hormone biosynthesis; gibberellin biosynthesis. Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed ubiquitously in roots, stems, leaves, flowers and siliques. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Gibberellin-deficient dwarf plants. Belongs to the terpene synthase family. Tpse subfamily.