PROBLEM TO BE SOLVED: To obtain a gene having low maltopentaose-decomposing activity and capable of obtaining maltopentaose in high yield and improving practical usability, by encoding α-amylase capable of highly producing maltopentaose, having a specific amino acid sequence.
SOLUTION: This gene encodes α-amylase capable of highly producing maltopentaose having an amino acid sequence wherein an amino acid 57th or 139 site is substituted in the amino acid sequence of maltopentaose-producing amylase derived from Pseudomonas sp. KO (Shida, O. et al., BiosciBiotech. Biochem. Vol. 56, 76-80, 1972). Preferably, a plasmid integrated with this gene has an amino acid sequence, e.g. of the formula. The other objective transformed E. coli having the plasmid containing e.g. the amino acid sequence of the formula has been deposited as FERM BP-6116.