著者

アワング アズワン カリム ラフィア 三ツ井 敏明

出版者

日本応用糖質科学会

雑誌

Journal of applied glycoscience (ISSN:13447882)

巻号頁・発行日

vol.57, no.4, pp.245-264, 2010-10-20

参考文献数

55

被引用文献数

1

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カカオ(Theobroma cacao)は、多くの熱帯地域の国の重要な作物であり、チョコレートの原材料として栽培されている。カカオにおいても害虫耐性の付与など品種改良が望まれているが、その基礎となるカカオの生理・生化学、分子遺伝学についてはほとんどわかっていない。また、現時点ではカカオのゲノム情報も明らかにされていない。われわれは、カカオポッド果殻のプロテオームを明らかにするため2次元電気泳動(2-DE)/質量分析を行った。カカオポッドには大量のガムが含まれているため、ポッド果殻タンパク質をフェノール抽出/メタノール-酢酸アンモニア沈澱法により調製した。タンパク質試料を2-DEで分離し、コロイドCBBで染色したところ、2-DEゲル中において約700のタンパクスポットを検出することができた。244個のタンパクスポットについてトリプシン消化物のSPITC-誘導体を調製し、MALDI-TOF/TOF MSを用いたde novoシークエンシングを行った。この方法により144個のカカオポッド果殻タンパク質を同定することができた。同定されたタンパク質の大部分は代謝やエネルギー生産に関与するものであった。また、ポッドの成長・分化に関わるタンパク質も検出された。

著者

Hitomi Ichinose Kentaro Suzuki Mari Michikawa Haruna Sato Masahiro Yuki Kei Kamino Wataru Ogasawara Shinya Fushinobu Satoshi Kaneko

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2017_018, (Released:2017-12-29)

被引用文献数

9

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Highly thermostable β-mannanase, belonging to glycoside hydrolase family 5 subfamily 7, was purified from the culture supernatant of Talaromyces trachyspermus B168 and the cDNA of its transcript was cloned. The recombinant enzyme showed maximal activity at pH 4.5 and 85 °C. It retained more than 90 % of its activity below 60 °C. Obtaining the crystal structure of the enzyme helped us to understand the mechanism of its thermostability. An antiparallel β-sheet, salt-bridges, hydrophobic packing, proline residues in the loops, and loop shortening are considered to be related to the thermostability of the enzyme. The enzyme hydrolyzed mannans such as locust bean gum, carob galactomannan, guar gum, konjac glucomannan, and ivory nut mannan. It hydrolyzed 50.7 % of the total mannans from coffee waste, producing mannooligosaccharides. The enzyme has the highest optimum temperature among the known fungal β-mannanases and has potential for use in industrial applications.

著者

Akira Yamamori Yusuke Takata Eri Fukushi Jun Kawabata Hideki Okada Naoki Kawazoe Keiji Ueno Shuichi Onodera Norio Shiomi

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.64, no.4, pp.123-127, 2017-11-20 (Released:2017-11-20)

参考文献数

23

被引用文献数

1

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A fermented beverage of plant extracts (Super Ohtaka®) was prepared from about 50 kinds of fruits and vegetables. This natural fermentation was performed by yeast (Zygosaccharomyces spp. and Pichia spp.) and lactic acid bacteria (Leuconostoc spp.) and resulted in the production of a novel fructopyranose-containing saccharide, which was subsequently isolated using carbon-Celite column chromatography and preparative-HPLC. The structure of the saccharide was determined using MALDI-TOF MS and NMR, and the saccharide was identified as β-D-fructopyranosyl-(2→6)-β-D-fructofuranosyl-(2↔1)-α-D-glucopyranoside. This is the first description of this novel saccharide and its isolation from a natural source.

著者

小役丸 孝俊

出版者

日本応用糖質科学会

雑誌

Journal of applied glycoscience (ISSN:13447882)

巻号頁・発行日

vol.55, no.4, pp.235-244, 2008-10-20

参考文献数

13

被引用文献数

3 4

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メイン部とキャリヤー部からなるいわゆるスタインホール型(SH)段ボール製造用澱粉接着剤の高速接着時の必要物性を明確にするために,85℃で高濃度澱粉糊化液のせん断ひずみ初期のせん断弾性率,最大せん断応力値,せん断応力パターンと粘度をトウモロコシ,ハイアミローストウモロコシ(ハイロン-5),ワキシートウモロコシ,小麦,馬鈴薯,甘藷,タピオカの7種の澱粉について測定した.7種澱粉懸濁液糊化液の物性は澱粉種により大きく異なり,これら懸濁液糊化液と,7種の各澱粉をメイン部に使用してキャリヤー部にトウモロコシを用いたSH接着剤糊化液との85℃での物性比較から,SH接着剤の糊化液物性はメイン部澱粉懸濁液糊化液物性を大きく反映し,キャリヤー部糊化澱粉水溶液の添加はこれらの物性を増強した.せん断弾性率と最大せん断応力値は澱粉種により差異があった.また,澱粉濃度の増加により,85℃7種澱粉懸濁液糊化液の各せん断弾性率と最大せん断応力値は指数関数的に増加した.さらに,糊化液のせん断弾性率が表す弾性と最大応力までのひずみ量が表す柔軟性や流動性は個々の澱粉種により澱粉濃度増加による変化が特徴的に異なり,四つのタイプに分類された.弾性率が高い順序と最大応力までのひずみ量が小さな順序で整理すると,弾性率が高く最大応力までのひずみ量が少ないハイロン-5と,弾性率がやや高く最大応力までのひずみ量がやや少ない小麦・トウモロコシと,弾性率がやや低く最大応力までのひずみ量がやや大きな馬鈴薯・甘藷・タピオカと,弾性率が低く最大応力までのひずみ量の大きなワキシーと異なる四つのタイプに分類された.その結果,SH澱粉接着剤糊化液物性は使用する澱粉種によりその物性が異なることがより明白となった.また,弾性率は糊化澱粉粒の形状保持が良いハイロン-5や地上澱粉で高くなり,最大応力までのひずみ量はワキシーや地下澱粉で大きくなった.しかしながら,7種澱粉をメイン部に用いるSH接着剤にて片段試料と表ライナー原紙を170℃のホットプレートで加熱貼合して,ただちに剥離した際の初期接着性には,澱粉種による大きな相違はなかった.これらのことから,初期接着性には澱粉接着剤糊化液の澱粉粒構造の存在や弾性率の高さや最大応力値が最も優先する条件ではないと考えられた.

著者

新名 惇彦

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.50, no.2, pp.345-349, 2003-04-20 (Released:2010-06-28)

参考文献数

4

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World population reached 6.1 billion in 2002 and it will become 9.5-10 billion in 2050. Programs for increasing crop yield are (1) Expansion of arable land, (2) Increase of yield per unit area, and (3) Plant breeding, but the former 2 programs can not be expected. The remaining possibility is plant breeding, i.e., development of high-yield and high-quality varieties and exploitation of stress-tolerant plants for extensive farming. Various physical and biological environmental stresses reduce the productivity of plants by 80% even in US. Traditional plant breeding by crossing requires at least a decade to establish improvement of one trait. Only one possible solution is a molecular breeding of plants. Transgenic crops with characters of herbicide-, insect-, and virus-resistance, long-life, high oleic and lauric acids content were produced. Safety assessment ofgenetically modified plants as food and feed is judged in various aspects. a) Effect of gene disruption on productionof toxic compounds. b) Transfer of maker gene, such as antibiotics-resistant gene, to intestinal microbes. c) Toxicity and allergen of foreign protein. These items were carefully studied by chemical analysis of transgenic plants, sequence of transgene, comparison of structure of transgene product (protein) with known toxic proteins and allergenic proteins, digestibility of proteins in stomach and intestine, and animal test. In conclusion, foods and feeds from transgenic plants so far certificated were substantially identical to usual foods and feeds.

著者

小林 正則 久保田 倫夫 松浦 良樹

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.50, no.1, pp.1-8, 2003-01-20 (Released:2011-02-23)

参考文献数

33

被引用文献数

4 18

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マルトオリゴシルトレハロース合成酵素(MTSase)はトレハロース生合成経路の第一段階で働く酵素であり,マルトオリゴ糖の還元末端のα-1,4結合を主として分子内転移によりα,α-1,1結合に変化させる反応を効率よく触媒する.筆者らは本酵素の立体構造を精密に(1.9A分解能)X線結晶解析し,反応機構について知見を得た.MTSaseはα-アミラーゼファミリーの酵素であり,触媒活性残基(Asp228,Glu255,Asp443)はファミリーに共通に保存されたものであり,α-1,4結合の解裂に続いてグルコースの転位が起こると考えられる.全体的な構造はファミリーに共通にみられる(β/α)8-バレルが存在し(ドメインA),活性部位はその中心β-バレルのc末端側とドメインBとの間に形成されたクレフトの底に位置している.通常のα-アミラーゼに比して挿入されたポリペプチド部分が多く,全体の分子量を大きくしている(720残基).活性部位はクレフトの一端の奥に存在し,三つの活性残基を底部に有したポケットを形成している.ポケット形成には上記挿入ポリペプチド部が大きく関与している.またポケット上部には触媒活性に必須なGlu393,側面にHis229が存在し,それぞれ末端グルコース基との水素結合に関与している.基質のα-1,4結合末端が挿入された際にポケット内部で形成される酵素・基質問の水素結合の数は,α,α-1,1結合を形成することにより増加し,その結果トレハロース残基の生成が促されると考えられる.

著者

Akira Yamamori Yusuke Takata Eri Fukushi Jun Kawabata Hideki Okada Naoki Kawazoe Keiji Ueno Shuichi Onodera Norio Shiomi

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2015_004, (Released:2015-04-03)

被引用文献数

3

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Ten difructose anhydrides (DFAs) were the predominant products formed from the thermal treatment of equal amounts of D-glucose and D-fructose under melting conditions at 150°C for 60 min. The DFAs were isolated from the reaction mixture by carbon-Celite column chromatography and preparative high-performance liquid chromatography. The structures of the saccharides were confirmed by NMR measurements. We present the complete assignments of the 1H- and 13C-NMR signals of two of these DFAs for the first time.

著者

Keiji Ueno Satoru Yokoshima Yuki Sasajima Yojiro Ishiguro Midori Yoshida Norio Shiomi Shuichi Onodera

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2014_012, (Released:2015-02-06)

被引用文献数

1 5

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Edible burdock (Arctium lappa L.) accumulates an inulin-type fructan. Inulin-type fructan in plant has been hydrolyzed by fructan 1-exohydrolases (1-FEH). We have previously reported on the cloning of aleh1, which encodes a 1-FEH in edible burdock. Here, we describe the cloning of aleh2, which encodes a 1-FEH isozyme in edible burdock, and the functional analysis of the recombinant protein of aleh2 (rAlEH2) that displays properties different from the aleh1 recombinant protein. A cDNA, named aleh2, was obtained by the RACE. The rAlEH2, which was produced by Pichia pastoris, showed 1-FEH activity. Unlike the recombinant protein of aleh1, the rAlEH2 is a 1-FEH enzyme that efficiently hydrolyzes longer-chain fructans than 1-kestose, such as nystose, fructosylnystose and inulin. The expression study in burdock revealed the induction of aleh1 and aleh2 genes by low temperature. These findings indicated that two 1-FEH isoforms were involved in the degradation of the fructan in burdock roots during low-temperature storage.

著者

Betzabe Linares Violante Arisa Minami Takashi Koyanagi Toshihiro Yano Mitsuru Ebihara Yuji Honda

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2014_008, (Released:2014-12-09)

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Lysozyme was purified from brown eared pheasant (Crossoptilon mantchuricum) egg white using pH treatment and cation exchange chromatography resulting in an 80-fold enhancement of the specific activity. The enzyme exhibited hydrolytic activity toward glycol chitin and chitooligosaccharides [(GlcNAc)n (n=5 and 6)]. The enzyme catalyzed degradation of bacterial cells of not only Micrococcus luteus but also Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 upon treatment with chloroform/tris(hydroxymethyl)aminomethane-HCl. The pH optimum of the glycol chitin hydrolytic reaction was 5.5 at 37°C. The optimal temperature for activity was 53°C in 50 mM sodium acetate buffer (pH 5.5). The enzyme mainly hydrolyzed the fourth glycosidic linkage from the nonreducing end of (GlcNAc)6. The anomeric form of the products indicated it was a retaining enzyme.

著者

Norihisa Hamaguchi Hirokazu Hirai Kenta Aizawa Masayasu Takada

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2014_009, (Released:2014-12-09)

被引用文献数

1 17

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Water-soluble dietary fiber provides numerous health benefits. A novel procedure to efficiently manufacture water-soluble indigestible polysaccharides was developed by heating glucose at 180°C in the presence of activated carbon. Aside from its ability to catalytically assist the polycondensation of saccharides, activated carbon provides the added benefits of being easily separable from the reactants and suppressing coloration of the product. Prior to purification, the indigestible fraction made up over 80% of the reaction mixture. After hydrolysis catalyzed by α-amylase and glucoamylase, and fractionation by ion-exchange chromatography, a total of 99.7% dietary fiber content was attained. This indigestible fraction, termed resistant glucan, was only minimally degraded by upper digestive tract enzymes, similar to the digestibility of polydextrose. Structural analysis by methylation and NMR indicated that the resistant glucan formed a highly branched structure containing α- and β-1,2-, 1,3-, 1,4-, and 1,6-linkages. On an industrial scale, the resistant glucan was obtained from glucose syrup (DE 86) by heating with activated carbon, enzymatic hydrolysis, refining, fractionating, and drying. Our facile method is an efficient means to obtain water-soluble dietary fiber.

著者

Michiko Shimokawa Kanefumi Kitahara Kiyotaka Fujita

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2014_006, (Released:2014-11-04)

被引用文献数

5

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We characterized a β-L-arabinopyranosidase AbpBL (BLLJ_1823) belonging to the glycoside hydrolase family 27 (GH27) from Bifidobacterium longum subsp. longum JCM1217. The recombinant AbpBL expressed in Escherichia coli hydrolyzed pNP-β-L-arabinopyranoside but not pNP-α-D-galactopyranoside. The enzyme also liberated L-arabinose from the β-L-arabinopyranosyl side chain of larch wood arabinogalactan. However, we could not detect any β-L-arabinopyranosidase activity or remarkable transcriptional induction in cultured cells of B. longum subsp. longum. Mutagenesis experiments revealed that I56D and I56A mutants both exhibited β-L-arabinopyranosidase and α-D-galactopyranosidase activities. AbpBL Ile-56 residue is a critical residue for the specificity of β-L-arabinopyranosidase.

著者

Yuri Kasuya Kazuhiro Natori Makoto Hattori Tadashi Yoshida Noriki Nio Koji Takahashi

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.109-112, 2014 (Released:2014-11-20)

参考文献数

24

被引用文献数

1

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A cross-linked (CL) collagen peptide (CP)-potato starch (PS) compound (CL-CP-PS) was prepared by autoclaving PS and CP and subsequently cross-linking with a microbial transglutaminase (MTGase). CP-compounded PS (CP-PS) was prepared by autoclaving a mixture of PS and CP at 120°C for 120 min. After suspending in an MTGase solution, CP-PS was cross-linked with MTGase at room temperature for 24 h while shaking. The reaction product was washed three times with distilled water, and then air-dried to obtain CL-CP-PS. CL-CP-PS showed a clear polarized image almost the same as that of PS, and had a 0.7% CP content. The median diameter of CL-CP-PS was significantly larger than that of CP-PS or of PS, suggesting the formation of multiple granules through cross-linking among the compounded CP moieties. CL-CP-PS exhibited a grater thermal structural stability, lower swelling index and solubility, as well as higher heat resistance for maintaining the swollen starch granules at 120°C for 20 min than those of CP-PS and PS. Cross-linking of CP-PS with MTGase should thus be valuable for providing a starch material having high rigidity, low swelling index and solubility, and enhanced heat resistance.

著者

Yoji Kato Donald J. Nevins

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.105-108, 2014 (Released:2014-11-20)

参考文献数

10

被引用文献数

1

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The water-insoluble fraction of Zea mays L. hybrid B73×Mo17 shoot cell walls, pretreated with purified Bacillus subtilis (1→3), (1→4)-β-D-glucan 4-glucanohydrolase and purified B. subtilis endo-(1→4)-β-D-xylanase, was subsequently treated with a glucuronoxylan xylanohydrolase preparation, all of which were obtained from a commercially available B. subtilis α-amylase (Novo Ban 120). Carbo­hydrates (about 16% of the original water-insoluble fraction of Zea shoot cell-walls) derived from the enzyme treatment contained significant amounts of galactan and (1→4)-β-D-galactobiose in addition to glucuronoarabinoxylan and neutral sugar residues-containing rhamnogalacturonan fragments. Methy­lation analysis and partial acid-hydrolysis of the isolated galactan followed by analysis of the hydrolyzate showed that the galactan consisted of about 14 (1→4)-β-consecutively linked galactose moieties.

著者

Akira Yamamori Hideki Okada Naoki Kawazoe Kei Muramatsu Shuichi Onodera Norio Shiomi

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.99-104, 2014 (Released:2014-11-20)

参考文献数

30

被引用文献数

2 13

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We have previously observed that the Super Ohtaka®, produced by fermenting extracts from 50 types of fruits and vegetables, contained the disaccharide, α-D-fructofuranosyl-(2→6)-D-glucose (α-Ff2→6G), which was produced during the fermentation process. α-Ff2→6G was also formed from equal amounts of D-glucose and D-fructose under melting conditions at 130°C for 45 min or at 140°C for 30 min. This disaccharide was isolated from the reaction mixture by carbon-Celite column chromatography and preparative- high performance liquid chromatography. It was confirmed to be α-Ff2→6G by matrix-assisted laser desorption ionization/time of flight mass spectrometry analysis and nuclear magnetic resonance measurements. The characteristics of α-Ff2→6G were investigated. The saccharide showed low digestibility and was 0.25 times as sweet as sucrose. Furthermore, unfavorable bacteria such as Enterobacter cloacae 1180, Escherichia coli 1099 and Clostridium perfringens 1211 that produce mutagenic substances did not break down the synthetic oligosaccharide.

著者

Tetsuya Oguma Satoshi Kitao Mikihiko Kobayashi

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.93-97, 2014 (Released:2014-11-20)

参考文献数

20

被引用文献数

8

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The enzyme cycloisomaltooligosaccharide glucanotransferase (CITase) was isolated from Bacillus circulans U-155, which had a yield of 25.8%, and purified to homogeneity. The Mr was approximately 98,000, similar to that for all known CITases. Specific activity of the purified enzyme was 2.11 U/mg protein, with maximal activity at approximately pH 6.0. The enzyme was stable at pH 4.5 up to pH 9.0 and at temperatures up to 50°C. The main product of the initial enzyme reaction was cycloisomalto-heptaose. The cit gene has a 2,895-bp open reading frame and encodes CITase in B. circulans U-155. We cloned this gene into a recombinant plasmid pCI811 and expressed it in Escherichia coli. A comparison between DNA sequence data from the transformant and the N-terminal amino acid sequence of the purified enzyme from B. circulans U-155 suggested that CITase was translated as a secretory precursor with a 30-amino-acid signal peptide. The mature enzyme contained 934 residues with a predicted molecular mass of 103.93 kDa. The enzyme activity in the transformants was approximately 3.0 mU/mL, similar to that of the purified enzyme secreted by B. circulans U-155. The enzyme also showed 72 and 67% identity with CITase from Paenibacillus sp. 598K and B. circulans T-3040, respectively. These results suggest that the enzyme isolated from B. circulans U-155 shares a greater similarity with CITase expressed by Paenibacillus sp. 598K than B. circulans T-3040.

著者

Nongluck Jaito Wataru Saburi Hirohiko Muto Hirokazu Matsui Haruhide Mori

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.117-119, 2014 (Released:2014-11-20)

参考文献数

19

被引用文献数

2 5

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Spectrophotometric quantification method of carbohydrates is useful for processing multiple samples. In this study, we established colorimetric quantification for 4-O-β-D-mannosyl-D-glucose (Man-Glc) and β-(1→4)-mannobiose (Man2). For quantification of Man-Glc, phosphorolysis of Man-Glc catalyzed by 4-O-β-D-mannosyl-D-glucose phosphorylase (MGP) was coupled with quantification of D-glucose by the glucose oxidase-peroxidase method. In addition to MGP, cellobiose 2-epimerase (CE) was added for quantification of Man2. In both quantifications, a good linear relationship was obtained between A505 and the sample concentration (0-0.5 mM). The A505 values obtained at various concentrations of Man2 and Man-Glc were almost identical to those with equivalent D-glucose concentrations. Kinetic parameters of Ruminococcus albus and Rhodothermus marinus CEs for the epimerization of Man2 were determined using the quantification method for Man-Glc. Both enzymes showed 5-15-fold higher kcat/Km values than those for cellobiose and lactose, which supports the prediction that these enzymes utilize Man2 as a substrate in the β-mannan metabolic pathway.

著者

Tomoyo Nishihira Asami Miyano Takayuki Ohnuma Takeshi Gotoh Saori Takahashi Kazue Narihiro Kazuhiko Yamashita Tamo Fukamizo

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.61, no.4, pp.113-116, 2014 (Released:2014-11-20)

参考文献数

16

被引用文献数

2

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A simple turbidimetric assay using chitin nanofiber as the substrate was employed to measure chitinase activity. The higher dispersive properties of chitin nanofibers enabled the degradation of chitin to be monitored turbidimetrically. When non-processive chitinases, a family GH18 chitinase from the tobacco plant and a GH19 chitinase from rye seeds, were added to the β-chitin nanofiber suspension, no significant changes were observed in the turbidity of the suspension, however, the amounts of reducing sugars produced were significantly high and small amounts of GlcNAc and (GlcNAc)2 were detected by HPLC in the reaction mixture. However, the addition of a processive family GH18 chitinase, Serratia marcescence chitinase B or chitinase from Autographa californica multiple nucleopolyhedrovirus, resulted in a significant decrease in the turbidity of the chitin nanofiber suspension, and produced larger amounts of reducing sugars including GlcNAc and (GlcNAc)2. The rate of decreases in turbidity was clearly dependent upon the enzyme concentration. We concluded that the turbidimetric assay using β-chitin nanofibers as the substrate was useful for measuring the activities of processive chitinases.

著者

Marie S. Møller Darrell Cockburn Jonas W. Nielsen Johanne M. Jensen Malene B. Vester-Christensen Morten M. Nielsen Joakim M. Andersen Casper Wilkens Julie Rannes Per Hägglund Anette Henriksen Maher Abou Hachem Martin Willemoës Birte Svensson

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2012_023, (Released:2013-03-21)

被引用文献数

1 1

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Certain enzymes interact with polysaccharides at surface binding sites (SBSs) situated outside of their active sites. SBSs are not easily identified and their function has been discerned in relatively few cases. Starch degradation is a concerted action involving GH13 hydrolases. New insight into barley seed α-amylase 1 (AMY1) and limit dextrinase (LD) includes i) kinetics of bi-exponential amylopectin hydrolysis by AMY1, one reaction having low Km (8 µg/ml) and high kcat (57 s-1) and the other high Km (97 µg/ml) and low kcat (23 s-1). β-Cyclodextrin (β-CD) inhibits the first reaction by binding to an SBS (SBS2) on domain C with Kd = 70 µM, which for the SBS2 Y380A mutant increases to 1.4 mM. SBS2 thus has a role in the fast, high-affinity component of amylopectin degradation. ii) The N-terminal domain of LD, the debranching enzyme in germinating seeds, shows distant structural similarity with domains including CBM21 present in other proteins and involved in various molecular interactions, but no binding site identity. LD is controlled by barley limit dextrinase inhibitor (LDI) which belongs to the cereal-type inhibitor family and forms a tight 1:1 complex with LD. iii) LDI in turn is regulated by disulfide reduction mediated by the barley thioredoxin h (trxh) NADPH-dependent thioredoxin reductase (NTR) system. Based on the progress monitored by released free thiol groups from LDI and its failure to inhibit LD as elicited by trxh, the LDI inactivation is proposed to stem from loss of structural integrity due to reduction of all four disulfides.

著者

大櫛 祐一 坂本 正弘 東 順一

出版者

日本応用糖質科学会

雑誌

Journal of applied glycoscience (ISSN:13447882)

巻号頁・発行日

vol.55, no.4, pp.231-234, 2008-10-20

被引用文献数

6

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前報(Ookushi <i>et al.: J. Appl. Glycosci</i>., <b>55</b>, 225-229 (2008))に引き続いて抽出方法を検討した結果,ヤマブシタケ子実体に含まれるglucanの92.7%を抽出することに成功した.その内訳は,42.3%がアルカリ抽出,17.7%が酵素処理-マイクロ波照射,10.7%が再度アルカリ抽出によって抽出された(Table 1).残りの22.0%はマイクロ波加熱熱水抽出により抽出される水可溶(1→3;l→6)-β-<small>D</small>-glucanである(Ookushi <i>et al.: J. Appl. Glycosci</i>., <b>53</b>, 267-272 (2006)).熱水抽出残渣に含まれるglucanの構造をメチル化分析により解析した結果,全て(1→3;1→6)-β-<small>D</small>-glucanに属し,次の三つの異なった存在形態を有していることが明らかとなった.(1)水素結合により強いネットワークを形成している(1→3)結合に富んだタイプ,(2)タンパク質・キチンと複合体を形成している(1→6)結合に富んだタイプ,および(3)タンパク質・キチンと複合体を形成している(1→3)結合に富んだタイプであった.

著者

大櫛 祐一 坂本 正弘 東 順一

出版者

日本応用糖質科学会

雑誌

Journal of applied glycoscience (ISSN:13447882)

巻号頁・発行日

vol.56, no.3, pp.153-157, 2009-07-20

被引用文献数

6

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含水下マイクロ波加熱(140°C, 5分)を利用して抽出したヤマブシタケ子実体に含まれる多糖類の特徴を, 通常の外部加熱を用いた熱水抽出(100°C, 6時間)から得た多糖類の化学構造と比較検討することにより解析した. サイズ排除クロマトグラフィーおよび陰イオン交換クロマトグラフィーにより分画した主な多糖類は, 通常の外部加熱ではfucogalactanと(1→6)結合に富んだ(1→3;1→6)-β-<small>D</small>-glucanであったのに対し, マイクロ波加熱の場合では(1→3)結合に富んだ(1→3;1→6)-β-<small>D</small>-glucanであった. マイクロ波加熱抽出物の低分子画分(M-3 fraction)に含まれるgalactose, fucoseの含量がかなり高くなっていたことから, マイクロ波加熱では, fucogalactanは低分子化していることが示唆された(Table 2). また, メチル化分析の結果(Table 3)から, 通常の外部加熱により得られる(1→3;1→6)-β-<small>D</small>-glucanの(1→6)結合のうち22.5%がマイクロ波加熱中に開裂していることが予想された. 本研究の結果より, ヤマブシタケ子実体から(1→3)結合を多く含むβ-glucanを抽出する上で, 通常の外部加熱を用いた熱水抽出よりも含水下マイクロ波加熱抽出の方が有効であることが示された.