| abstract |
It is intended to provide a heat-stable sucrose phosphorylase (SP) obtained by modifying natural SP and a method of preparing this heat-stable SP. Namely, a heat-stable SP which has an amino acid residue differing from the one in natural sucrose phosphorylase at least one position selected from the group consisting of: the positions corresponding respectively to the 14-, 29- and 44-positions in the motif sequence 1; the positions corresponding respectively to the 7-, 19-, 23- and 34-positions in the motif sequence 2; and the position corresponding to the 19-position in the motif sequence 3, and, after heating in a 20 mM Tris buffer solution (pH 7.0) at 55°C for 20 minutes, shows an enzymatic activity amounting to 20% or more of the enzymatic activity of the unheated heat-stable SP at 37°C. |