Functional Characteristics of a Bacterial Dextrin Dextranase from Acetobacter capsulatum ATCC 11894.
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- Suzuki Masayuki
- The Graduate School of Electronic Science and Technology, Shizuoka University
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- Unno Takehiro
- Research Institute, Nihon Shokuhin Kako Co., Ltd
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- Okada Gentaro
- The Graduate School of Electronic Science and Technology, Shizuoka University Department of Biology, Faculty of Education, Shizuoka University
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Dextrin dextranase (DDase, EC 2.4.1.2) was extracellularly secreted in a culture medium of Acetobacter capsulatum ATCC 11894 containing both glucose and a small amount of dextrin as the essential carbon sources. The enzyme was simply purified by a high-speed refrigerated centrifugation, and immediately dialyzed against 50 mM acetate buffer (pH 4.5). The purified DDase gave a single protein band on both Native- and SDS-PAGE. The molecular mass of the purified enzyme was estimated to be about 152 kDa (SDS-PAGE). The optimum pH and temperature of the enzyme were 5.2 and 38°C, respectively. The Km (mM) and Vmax (mg dextran/mg protein/min) values for mal-tooligosaccharides (DP 3-7) and short-chain amylose (DP 17.3) were estimated to be about 10.2, 1.74; 6.41, 2.56; 3.34, 2.64; 2.59, 2.39; 1.66, 2.17; 0.12, 2.23, respectively. The conversion rate of maltodextrins into dextran increased with the increases in the DP number of donor sub-strates. The maximum yield of product dextran reached 73.9% by using short-chain amylose as a substrate. DDase showed a strong affinity on the sugars having non-reducing terminal linked with either α-1, 4- to α-1, 6-glucosidic bond. The affinity of enzyme on acceptor substrates increased with the increases in the DP number of sugars tested. Various oligosaccharides were formed, when DDase reacted on a maltose-dextran mixture. The ratio of α-1, 4- to α-1, 6-glucosidic linkages in a product dextran molecule was calculated to be about 1: 20. The average molecular mass of product dextran was estimated to be about 1270 kDa. The chemical structures of synthesized glucooligo-saccharides (DP =3-7) from a maltose-dextran mixture were 4-ο-α-isomaltosyl-D-glucose, 4-ο-α-isomaltotriosyl-D-glucose, 4-ο-α-isomaltotetraosyl-D-glucose, 4-ο-α-isomaltopentaosyl-D-glucose and 4-ο-α-isomaltohexaosyl-D-glucose. On the basis of many experimental data, we propose the possible transglucosylation actions of DDase which consist of five reaction routes.
収録刊行物
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- Journal of Applied Glycoscience
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Journal of Applied Glycoscience 48 (2), 143-151, 2001
日本応用糖質科学会
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詳細情報 詳細情報について
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- CRID
- 1390001206294117376
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- NII論文ID
- 10008252572
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- NII書誌ID
- AN10453916
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- COI
- 1:CAS:528:DC%2BD3MXjslGnu74%3D
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- ISSN
- 18807291
- 13447882
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- NDL書誌ID
- 5764595
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- NDL
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