Quantitative Study of the Anomeric Forms of Isomaltose and Glucose Produced by Isomalto-dextranase and Glucodextranase

Molecular cloning and expression of an isomalto-dextranase gene from Arthrobacter globiformis T6

“…Furthermore, the predicted amino acid composition of the mature protein was consistent with that of the purified IMD. The relative molecular weight (Mr, 65,900) of the deduced mature protein agreed very closely with that (Mr, 66,000) of the purified enzyme (32). These Our data on the expression of the imd gene showed that E. coli cells recognized a promoter on the genomic fragment of A. globiformis T6.…”

“…In 1974, Sawai et al described a bacterial isomalto-dextranase (IMD) (EC 3.2.1.94; 1,6-a-D-glucan isomaltohydrolase) that was a novel exo-type enzyme capable of hydrolyzing dextran to release isomaltose units successively from the nonreducing ends of dextran chains (26,27). This enzyme is produced extracellularly by Arthrobacter globifonnis T6, a gram-positive soil bacterium identified by Sawai et al (26), and some properties of the purified enzyme have been reported by Sawai et al and by our group (18,32,34). Isomaltose, the sole product generated from dextran by this enzyme, inhibits the biosynthesis of mutan (7), which is a water-insoluble glucan composed predominantly of a-1,3-linked glucose units.…”

“…globiformis T6 (NRRL B-4425, IMA 12103). The enzyme preparation was obtained by methods described previously (18,32) and purified further by fast-performance liquid chromatography on a Mono-S column (Pharmacia Fine Chemical, Uppsala, Sweden). The purified IMD (6 nmol) was digested with 60 pmol of protease I from Achromobacter lyticus (Lys-C protease; Wako Pure Chemical Ind., Ltd., Osaka, Japan) at 30°C for 20 h. The resulted peptides were separated by reverse-phase high-performance liquid chromatography on a TRI ROTER-VI system (Japan Spectroscopic Co., Ltd., Tokyo, Japan) equipped with a Finepak C8-P column (Asahi Chemical Industry, Co., Ltd., Tokyo, Japan).…”

α-Glucosidase Mutant Catalyzes “α-Glycosynthase”-type Reaction

“…In the hydrolysis (Scheme 1(C)-I), the a-glucosidic linkage in each substrate is inverted to release a b-product, namely bglucose or b-maltose. [17][18][19][20] In the oligosaccharide production, Hehre and co-workers have shown that glucoamylase, glucodextranase, and trehalase of inverting enzymes synthesized a-conˆgurational products from b-glucose or b-GF, 11,12) and that bamylase synthesized an a-conˆgurational product from b-maltose or b-maltosyl ‰uoride.…”

Crystal Structure and Mutational Analysis of Isomalto-dextranase, a Member of Glycoside Hydrolase Family 27

“…(3). The A. globiformis T6 enzyme (abbreviated as AgIMD) 3 liberates isomaltose from the nonreducing end of dextran and isomalto-oligosaccharides through a retaining mechanism (4,5). AgIMD also catalyzes transglycosylation, and the enzymatic synthesis of some oligosaccharides using AgIMD has been reported (6).…”