There is disclosed are an enzyme preparation characterized by a polymer carrier
having fine pores with average radius of 200-500 and the enzyme is capable
of converting an N-substituted cyclic imino ester into an (S)-N-substituted cyclic
imino acid, thereby an (S)-N-substituted cyclic imino acid is preferentially produced,
and has an amino acid sequence as set forth in SEQ ID NO: 1 or the like.