Patent ID: 7241606

Claim:
A purified α-isomatosylglucosaccharide-forming enzyme which forms a saccharide having a glucose polymerization degree of at least three and having both the α-1,6 glucosidic linkage as a linkage at the non-reducing end and the α-1,4 glucosidic linkage other than the linkage at the non-reducing end, by catalyzing α-glucosyl-transfer from a saccharide having a glucose polymerization degree of at least two and having an α-glucosidic linkage at the non-reducing end; which enzyme comprises an amino acid sequence of SEQ ID NO:1, SEQ ID NO:11 or SEQ ID NO:18 as a partial amino acid sequence; said enzyme being incapable of forming dextran, said enzyme being inhibited by EDTA, and said enzyme activated by Ca 2+ and Mn 2+ ; thermal stability of said enzyme being improved by Ca 2+ ; and said enzyme having the following physicochemical properties: a. Molecular weight About 136,000±20,000 Daltons on SDS-PAGE; b. Isoelectric point (pI) About 7.3±0.5 on isoelectrophoresis using ampholine; c. Optimum temperature (i) About 50° C. when incubated at a pH of 6.0 for 60 minutes; (ii) About 55° C. when incubated at a pH of 6.0 for 60 minutes in the presence of 1 mM Ca 2+ ; d. Optimum pH About 6.0 when incubated at 35° C. for 60 minutes; e. Thermal stability (i) Stable up to a temperature of about 45° C. when incubated at a pH of 6.0 for 60 minutes; (ii) Stable up to a temperature of about 50° C. when incubated at a pH of 6.0 for 60 minutes in the presence of 1 mM Ca 2+ ; f. pH stability Stable at pHs of about 5.0 to about 9.0 when incubated at 4° C. for 24 hours.