in a series of oxiranes having a lipophilic substituent of sufficient size ( styrene oxides ) , monosubstituted as well as 1,1- and cis-1,2-disubstituted oxiranes readily served as substrates or inhibitors of the enzyme , but not the trans-1,2-disubstituted , tri- or tetra-substituted oxiranes . trans-substitution at the oxirane ring apparently prevents access of the oxirane ring to the active site by steric hindrance .
C0014630
oxiranes
C0015087
oxirane