This family contains tocopherol cyclases. These enzymes are involved in the synthesis of tocopherols and tocotrienols (vitamin E) [1].

1: Isolation of an Arabidopsis mutant lacking vitamin E and identification of a cyclase essential for all tocopherol biosynthesis. Porfirova S, Bergmuller E, Tropf S, Lemke R, Dormann P; Proc Natl Acad Sci U S A. 2002;99:12495-12500. PMID:12213958