Patent ID: 7709230

Claim:
A process for producing isomaltose, comprising the steps of: (a) allowing α-isomaltosylglucosaccharide-forming enzyme to act on a starting saccharide selected from the group consisting of maltooligosaccharides, maltodextrins, amylodextrins, amyloses, amylopectins, soluble starches, liquefied starches, and glycogens to form α-isomaltosylglucosaccharide having a glucose polymerization degree of at least three, an α-1,6 glucosidic linkage as a linkage at the non-reducing end, and α-1,4 glucosidic linkages at all positions except the linkage at the non-reducing end; said α-isomaltosylglucosaccharide-forming enzyme forms said α-isomaltosylglucosaccharide from said starting saccharide by catalyzing an α-glucosyl-transferring reaction without substantially hydrolyzing isomaltose, and said α-isomaltosylglucosaccharide forming enzyme is obtained from a microorganism of genus Bacillus or Arthrobacter; (b) allowing isomaltodextranase to act on the formed α-isomaltosylglucosaccharide to release isomaltose; and (c) collecting the released isomaltose wherein said α-isomaltosylglucosaccharide forming enzyme has the following physicochemical properties: (1) Molecular weight Having a molecular weight of about 117,000 to about 160,000 daltons when determined on SDS-PAGE; (2) Isoelectric point (pI) Having an isoelectric point of 4.7 to about 5.7 when determined on isoelectrophoresis using ampholine; (3) Optimum temperature Having a optimum temperature of about 40° C. to bout 45° C. when incubated at a pH of 6.0 for 60 min, or an optimum temperature of about 45° C. to about 50° C. when incubated in the presence of 1 mM Ca 2+ ; (4) Optimum pH Having an optimum pH of about 6.0 to about 6.5 when incubated at 35° C. for 60 min; (5) Thermal stability Stable up to a temperature of about 35° C. to 40° C. when incubated at pH 6.0 for 60 min, or a temperature of about 40° C. to about 45° C. when incubated in the presence of 1 mM Ca 2+ ; and (6) pH stability Stable at a pH of about 4.5 to about 10.0 when incubated at 4° C. for 24 hours.