Patent ID: 8389240

Claim:
A method of producing an α-L-aspartyl-L-phenylalanine-β-ester, comprising forming the α-L-aspartyl-L-phenylalanine-β-ester from L-aspartic acid-α,β-diester and L-phenylalanine using an enzyme or enzyme-containing substance that has an ability to selectively link L-phenylalanine to an α-ester site of the L-aspartic acid-α,β-diester through a peptide bond, wherein said enzyme or an enzyme in said enzyme-containing substance is selected from the group consisting of: a protein having the amino acid sequence consisting of amino acid residue 18 to 644 of SEQ ID NO:27, a protein having an amino acid sequence including substitution, deletion, insertion, and/or addition of one to thirty amino acids in the amino acid sequence consisting of amino acid residues 18 to 644 of SEQ ID NO:27, and having activity to selectively link L-phenylalanine to an α-ester site of the L-aspartic acid-α,β-diester through a peptide bond, a protein having the amino acid sequence of SEQ ID NO:27, and a protein containing a mature protein region, having an amino acid sequence including substitution, deletion, insertion, and/or addition of one to thirty amino acids in the amino acid sequence of SEQ ID NO:27, and having activity to selectively link L-phenylalanine to an α-ester site of the L-aspartic acid-α,β-diester through a peptide bond.