Patent ID: 7968309

Claim:
A purified sucrose phosphorylase having improved thermostability, which is obtained by modifying a natural sucrose phosphorylase, wherein the sucrose phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural sucrose phosphorylase in at least one position selected from the group consisting of: a position corresponding to position 14, a position corresponding to position 29 and a position corresponding to position 44 in motif sequence 1: AVGGVHLLPFFPSTGDRGFAPIDYHEVDSAFGDWDDVKRLGEKYYLMFDFMINHIS (SEQ ID NO. 25); a position corresponding to position 7, a position corresponding to position 19, a position corresponding to position 23 and a position corresponding to position 34 in motif sequence 2: RPTQEDVDLIYKRKDRAPKQEIQFADGSVEHLWNTFGEEQID (SEQ ID NO. 26); and a position corresponding to position 19 in motif sequence 3: ILPEIHEHYTIQFKIADHDYYVYDFALPMVTLYSLYSG (SEQ ID NO. 27); and wherein enzyme activity of the sucrose phosphorylase having improved thermostability at 37° C., after heating the sucrose phosphorylase having improved thermostability in 20 mM Tris buffer (pH 7.0) at 55° C. for 20 minutes, is 20% or more of enzyme activity of the sucrose phosphorylase having improved thermostability at 37° C., before heating wherein the amino acid sequence of the natural sucrose phosphorylase has at least 95% sequence identity to the sequence of SEQ ID N: 2.