著者
Shinya Fushinobu Masafumi Hidaka Andressa M. Hayashi Takayoshi Wakagi Hirofumi Shoun Motomitsu Kitaoka
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.58, no.3, pp.91-97, 2011 (Released:2011-09-07)
参考文献数
29
被引用文献数
5 6

Azasugars are known as potent inhibitors of glycoside hydrolases. In this study, we examined the inhibition of Cellvibrio gilvus cellobiose phosphorylase (CBP) by four azasugars (isofagomine, 1-deoxynojirimycin, castanospermine and calystegine B2) and a non-azasugar (glucono-1,5-lactone). Isofagomine strongly inhibited CBP, whereas 1-deoxynojirimycin, castanospermine, and glucono-1,5-lactone exhibited moderate or weak inhibition. Calystegine B2 did not inhibit CBP. Kinetic analysis in the presence of sulfate indicated that it is an extremely weak competitive inhibitor against phosphate. Moreover, crystal structures of CBP complexed with isofagomine or 1-deoxynojirimycin were determined, revealing molecular recognition of the glucosidase inhibitors by the phosphorolytic enzyme. These inhibitors are bound at subsite −1 and form several hydrogen bonds with the protein and anion (phosphate or sulfate). The strong inhibition by isofagomine is probably due to an electrostatic interaction between its endocyclic amino group and phosphate.
著者
大隈 一裕 松田 功 勝田 康夫 岸本 由香 辻 啓介
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.53, no.1, pp.65-69, 2006 (Released:2006-04-19)
参考文献数
27
被引用文献数
4 4

In 1988 we recognized glycosylated components in pyrodextrin and started a study to obtain an amylase-resistant ingredient. We succeeded in establishing a series of processes for industrial-scale separation of the indigestible component with superior appearance and taste by roasting starch (pyrolysis), enzymatic hydrolysis, purification, chromatographic fractionation and spray drying. The component was named indigestible dextrin (ID). In order to utilize ID as a source of dietary fiber, a low-calorie ingredient, and a physiologically active ingredient, we first confirmed that ID is a highly safe ingredient by conducting an acute toxicity study, a mutagenicity study, long-term administration studies in both rats and humans, and a study of diarrhea caused by long-term consumption. A novel determination method using the enzyme-gravimetric method in combination with high performance liquid chromatography (enzyme-HPLC method) was proposed to the Association of Official Analytical Chemists (AOAC) and approved as Final Action Method AOAC 2001. 03 in January 2005. Animal and human studies showed the energy value of 1 kcal/g dietary fiber fraction. Based on these results, ID has been approved in many countries. Moreover, it has been confirmed by both animal and clinical studies that ID has physiological functions such as intestinal regularity, moderating postprandial blood glucose level, lowering serum lipid, and reducing body fat. As for the physicochemical properties of ID, it is similar to DE10 maltodextrin in sweetness and browning property. The properties of not being fermented easily by yeast or lactobacillus impart an interesting characteristic to beer and lactic acid drinks. At present ID is commercially available for use in a wide range of food products not only in Japan but also in many countries around the world.
著者
大隈 一裕 松田 功 勝田 康夫 岸本 由香 辻 啓介
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.53, no.1, pp.65-69, 2006-01-20
参考文献数
27
被引用文献数
4

In 1988 we recognized glycosylated components in pyrodextrin and started a study to obtain an amylase-resistant ingredient. We succeeded in establishing a series of processes for industrial-scale separation of the indigestible component with superior appearance and taste by roasting starch (pyrolysis), enzymatic hydrolysis, purification, chromatographic fractionation and spray drying. The component was named indigestible dextrin (ID). In order to utilize ID as a source of dietary fiber, a low-calorie ingredient, and a physiologically active ingredient, we first confirmed that ID is a highly safe ingredient by conducting an acute toxicity study, a mutagenicity study, long-term administration studies in both rats and humans, and a study of diarrhea caused by long-term consumption. A novel determination method using the enzyme-gravimetric method in combination with high performance liquid chromatography (enzyme-HPLC method) was proposed to the Association of Official Analytical Chemists (AOAC) and approved as Final Action Method AOAC 2001. 03 in January 2005. Animal and human studies showed the energy value of 1 kcal/g dietary fiber fraction. Based on these results, ID has been approved in many countries. Moreover, it has been confirmed by both animal and clinical studies that ID has physiological functions such as intestinal regularity, moderating postprandial blood glucose level, lowering serum lipid, and reducing body fat. As for the physicochemical properties of ID, it is similar to DE10 maltodextrin in sweetness and browning property. The properties of not being fermented easily by yeast or lactobacillus impart an interesting characteristic to beer and lactic acid drinks. At present ID is commercially available for use in a wide range of food products not only in Japan but also in many countries around the world.
著者
檜作 進
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.46, no.2, pp.159-165, 1999-06-30 (Released:2010-06-28)
参考文献数
35
被引用文献数
5 9

L-Arabinose is a common component in a plant cell wall and is widely distributed in the plant kingdom. It is a main component of cereal hemicellulose, such as corn, wheat, rye, and rice, pectic substances of beet and apple pulps, and some plant gums. The sugar occurs in the free state in the heartwood of coniferous trees, but its small amounts have been found also in several foods and beverages made from cereals and other plant sources such as bread, miso, beer and tea. L-Arabinose is produced by the mild acid hydrolysis of some plant gums, corn fiber, and beet pulps. The taste of L-arabinose is quite similar to sucrose, but approximately half the sweetness . Naturally occurring arabinose is an L-form, and it is not metabolized in animals; thus it is a noncaloric sugar . Furthermore, it strongly inhibits intestinal sucrase uncompetitively and consequently inhibits the absorption of sucrose from the small intestine. The addition of 2-3% of L-arabinose to sucrose causes about a 60% reduction of the digestion of sucrose in the small intestine. The nondigested sucrose and L-arabinose, possibly metabolized by intestinal microbes, produce short-chain fatty acids and thus function similar to dietary fiber. L-Arabinose, by this function, reduces the increase of the levels of blood sugar, insulin, triglycerides, and cholesterol by the ingestion of sucrose . Therefore it has great merits as a sweetener and a food additive to improve the obesity and to maintain good health .
著者
Megumi Matsui Haruka Kono Makoto Ogata
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.65, no.3, pp.31-36, 2018-08-20 (Released:2018-08-20)
参考文献数
20
被引用文献数
1

A novel substrate {Galβ1,4GlcNAcβ1,4GlcNAc-β-pNP [Gal(GlcNAc)2-β-pNP]} for assaying lysozyme activity has been designed using docking simulations and enzymatic synthesis via β-1,4-galactosyltransferase-mediated transglycosylation from UDP-Gal as the donor to (GlcNAc)2-β-pNP as the acceptor. Hydrolysis of the synthesized Gal(GlcNAc)2-β-pNP and related compounds using hen egg-white lysozyme (HEWL) demonstrated that the substrate was specifically cleaved to Gal(GlcNAc)2 and p-nitrophenol (pNP). A combination of kinetic studies and docking simulation was further conducted to elucidate the mode of substrate binding. The results demonstrate that Gal(GlcNAc)2-β-pNP selectively binds to a subsite of lysozyme to liberate the Gal(GlcNAc)2 and pNP products. The work therefore describes a new colorimetric method for quantifying lysozyme on the basis of the determination of pNP liberated from the substrate.
著者
Takahito Kajiki Shiro Komba
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.66, no.3, pp.103-112, 2019-08-20 (Released:2019-08-28)
参考文献数
20

We have developed a novel low-molecular-mass oil-gelling agent that is electrically neutral, has no nitrogen atoms and consists only of cyclic sugar alcohols and saturated linear fatty acids. The cyclic sugar alcohols were 1,5-anhydro-D-glucitol (1,5-AG) and 1,5-anhydro-D-mannitol (1,5-AM) derived from starch via 1,5-anhydro-D-fructose. Various saturated linear fatty acids with 10 to 18 and 22 carbon atoms were introduced into all the hydroxy groups of 1,5-AG. Various saturated linear fatty acids with 13 to 18 and 22 carbon atoms were introduced into all the hydroxy groups of 1,5-AM. Initially, the gelling ability increased as the carbon number increased, but the gelling ability decreased as the carbon number increased beyond 17 carbons. This trend was similar for both 1,5-AG and 1,5-AM. A comparison of 1,5-AG and 1,5-AM derivatives revealed that 1,5-AG derivatives had greater gelling abilities for different kinds of oils at the same fatty acid length. Further, it was confirmed by SEM observations that a three-dimensional fibrous structure was formed, and this network structure formed the gel and held the oil. Here, we report the synthesis and characteristics of a novel low-molecular-weight gelling agent and its gelation mechanism.
著者
Junko Matsuki Masahisa Wada Tomoko Sasaki Koichi Yoza Ken Tokuyasu
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.66, no.3, pp.97-102, 2019-08-20 (Released:2019-08-28)
参考文献数
28
被引用文献数
1

Ethanol precipitation process for purification of branched dextrin (BD) in Nägeli amylodextrin from waxy rice starch was developed. Temperature and ethanol concentration for precipitation were main parameters affecting the recovery and purity of BD, and the purification condition at 4 °C and 10 % (v/v) ethanol in water was adopted. After four-time precipitation, the BD recovery was 34.6 %, whereas the purity improved from 78.5 % at the initial to 94.5 % at the four-time purified BD (BD4). BD4 mainly showed a chain length distribution between 18 to 35 with a mode length of 25, which shifted after enzymatic debranching with isoamylase to that between 9 and 20 with a mode length of 14. Each purified BD was solubilized in water, and each solution was mixed with methanol-water at 25 °C to a final methanol concentration of 16 M. The flakes of BD precipitated with 16 M methanol exhibited an A-type crystal structure by an X-ray diffraction analysis, and the speed generation of white flakes in 16 M methanol dramatically increased as the purification time increased. The effect of addition of highly branched cyclic dextrin (HBCD) or sodium tetraborate on BD aggregation in 16 M methanol was also investigated, where the former retarded aggregation but the latter had no effect on the velocity. Thus, the purified BD enables rapid characterization of aggregation of double helix structures of A-type crystal structure, and screening of compounds which could affect the phenomena for prediction of potentials in starch modification as well.
著者
Kiyoshi Kawai Iyo Uneyama Savitree Ratanasumawong Yoshio Hagura Ken Fukami
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.66, no.3, pp.89-96, 2019-08-20 (Released:2019-08-28)
参考文献数
33

Glass transition temperature (Tg) is an important parameter for the physical quality control of hard candies. In order to understand the applicability of calcium maltobionate to hard candy, effect of calcium maltobionate addition on the Tg of model and hand-made hard candies was investigated. Freeze-dried calcium maltobionate-sugar (sucrose containing a small amount of glucose-fructose mixture) and calcium maltobionate-reduced isomaltulose mixtures were prepared as model candies, and their anhydrous Tg was evaluated using a differential scanning calorimetry. The anhydrous Tg increased linearly with the molar fraction of calcium maltobionate. From these results, it was expected that calcium maltobionate can improve the physical stability of normal and sugarless candies. For comparison, various commercial candies were employed, and their Tg was evaluated using a thermal rheological analysis. The Tg values were in the range of 28–49 °C. The Tg values were higher than 25 °C, which is significant with respect to the physical stability of the candies. Calcium maltobionate-sugar and calcium maltobionate-reduced isomaltulose candies were prepared as hand-made candies. The calcium maltobionate-reduced isomaltulose candies had higher Tg than the calcium maltobionate-sugar candies at each calcium maltobionate content, although reduced isomaltulose has a lower Tg than sugar. At a high calcium maltobionate content, calcium maltobionate-reduced isomaltulose candy had an equivalent Tg to the commercial sugarless candies, and thus practically acceptable stability was expected. In the case of calcium maltobionate-sugar candies, there was a possibility that the hydrolysis of sugar reduced their Tg. Vacuum-concentration will be useful to improve the Tg of the candies.
著者
Naoki Shirasaka Koichi Harazono Ryota Nakahigashi Keigo Mitsui Jun Tanaka Sayaka Tanazawa Masaru Mitsutomi Takayuki Ohnuma
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.66, no.3, pp.83-88, 2019-08-20 (Released:2019-08-28)
参考文献数
29

We characterized SaHEX, which is a glycoside hydrolase (GH) family 20 exo-β-N-acetylhexosaminidase found in Streptomyces avermitilis. SaHEX exolytically hydrolyzed chitin oligosaccharides from their non-reducing ends, and yielded N-acetylglucosamine (GlcNAc) as the end product. According to the initial rate of substrate hydrolysis, the rates of (GlcNAc)3 and (GlcNAc)5 hydrolysis were greater than the rates for the other oligosaccharides. The enzyme exhibited antifungal activity against Aspergillus niger, which was probably due to hydrolytic activity with regard to chitin in the hyphal tips. Therefore, SaHEX has potential for use in GlcNAc production and food preservation.
著者
Tomoya Shintani Yuhei Kosuge Hisashi Ashida
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.65, no.3, pp.37-43, 2018-08-20 (Released:2018-08-20)
参考文献数
45
被引用文献数
2

Glucosamine (GlcN) is commonly used as a dietary supplement to promote cartilage health in humans. We previously reported that GlcN could induce autophagy in cultured mammalian cells. Autophagy is known to be involved in the prevention of various diseases and aging. Here, we showed that GlcN extended the lifespan of the nematode Caenorhabditis elegans by inducing autophagy. Autophagy induction by GlcN was demonstrated by western blotting for LGG-1 (an ortholog of mammalian LC3) and by detecting autophagosomal dots in seam cells by fluorescence microscopy. Lifespan assays revealed that GlcN-induced lifespan extension was achieved with at least 5 mM GlcN. A maximum lifespan extension of approximately 30 % was achieved with 20 mM GlcN (p<0.0001). GlcN-induced lifespan extension was not dependent on the longevity genes daf-16 and sir-2.1 but dependent on the autophagy-essential gene atg-18. Therefore, we suggest that oral administration of GlcN could help delay the aging process via autophagy induction.
著者
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
vol.65, no.2, pp.13-21, 2018-05-20 (Released:2018-05-20)
参考文献数
40
被引用文献数
2

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
小川 温子 天野 麻穂 土方 亜子 加藤 真利 上平 知子 末次 勧 石塚 稲夫
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.50, no.2, pp.327-331, 2003-04-20 (Released:2011-02-23)
参考文献数
13

Plant N -linked oligosaccharides of complex type generally possess a characteristic core structure with xylose β-2 linked to β-mannose and fucose a 1-3 linked to N-acetylglucosamine at the reducing end, which rarely found in animals. Such glycans of plant glycoproteins have been found to induce immunogenic responses in animals. This brief report introduces the current knowledge on the structure, antigenicity and allergenicity of plant carbohydrate epitopes (plant glycotopes) obtained from our studies on the allergens of Japanese cedar pollinosis and baker's asthma. It also presents relationship between CCD (cross-reactive carbohydrate determinant) of allergens from common vegetables or fruits and that of the Japanese cedar pollen in this study.
著者
五十嵐 俊成 花城 勲 竹田 靖史
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.1, pp.5-12, 2008 (Released:2008-04-03)
参考文献数
47
被引用文献数
5 6

澱粉の分子構造と糊化特性を北海道米「ほしのゆめ」,「きらら397」,「彩」を秋田米「あきたこまち」と比較して解析した.北海道米3品種の澱粉の結晶型はCa型,「あきたこまち」はA型を示した.真のアミロース含量は,「ほしのゆめ」,「きらら397」が18%で「彩」,「あきたこまち」より約2%高かった.RVAによる熱糊化特性は「ほしのゆめ」,「きらら397」で最高粘度が低く,ブレイクダウンが小さく,冷却時の粘度増加が高いが,「彩」,「あきたこまち」は最高粘度が高く,冷却時の粘度増加は低かった.アミロースのヨウ素親和力は「ほしのゆめ」,「きらら397」が約19で「彩」,「あきたこまち」よりわずかに小さく,数平均重合度(DPn)は「ほしのゆめ」と「きらら397」が「あきたこまち」とほぼ同じ(~900)で,「彩」(~1000)がやや大きかった.平均鎖数は2~3であった.数分布は北海道3品種とも「あきたこまち」より広かった.アミロペクチンのヨウ素親和力は「ほしのゆめ」,「きらら397」が0.5で,「彩」,「あきたこまち」より2.5倍高く,DPnは「あきたこまち」(9400)が最も大きく,「彩」(7600)が最も小さかった.平均鎖長は北海道3品種が19で「あきたこまち」より1-2残基短く,β-アミラーゼ分解限度は「あきたこまち」よりわずかに高かった.アミロペクチンLC含量は,「ほしのゆめ」と「きらら397」は「あきたこまち」に比べて約3.5倍であった.以上のことから,「彩」は見かけのアミロース含量が「あきたこまち」と同じ程度で,他の北海道品種に比べ冷却時の粘度増加も改善されているが「あきたこまち」よりも高く,熱糊化特性の差異の要因としてアミロース分子量分布やアミロペクチン鎖長分布の影響が示唆された.したがって,今後の良食味育種では低アミロース含量の選抜に加えて澱粉の分子構造に着目し,特にアミロペクチン超長鎖(LC)の少ない品種選抜が必要と考えられる.
著者
菊田 千景 川西(朝岡) 正子 大谷 弥里 杉本 温美
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.56, no.4, pp.287-293, 2009
被引用文献数
1

世界各国から集めたジャガイモを日本の気候風土に合わせて栽培した,テイスティングポテトと呼ばれる10品種のジャガイモ(アンデスレッド,インカのめざめ,ジャガキッズパープル,ビオレッタ,タワラムラサキ,デストロイヤー,十勝こがね,ヨーデル,シェリー,シンシア)を,2°Cで2カ月ならびに7カ月貯蔵し,それらから単離した澱粉の理化学的特性に及ぼす低温貯蔵の影響を調べた.分析した項目は,粒度分布,X線回折,ラピッドビスコアナライザー(RVA)による糊化特性,示差走査熱分析,リン含量,アミロース含量,溶解度および膨潤度,酵素分解ならびに走査電子顕微鏡による観察である.テイスティングポテトの澱粉は,低温下での貯蔵期間が延長することにより,X線回折図形はB図形のままで変化がなかったが,RVAのセットバック,酵素分解性ならびにアミロース含量が増加する傾向にあった.しかし,その他の理化学的特性は,品種により変動はさまざまで,一貫性がほとんどなく,各品種の原産地などとの関連についても認められなかった.
著者
Seigo Murakami Mai Kuramochi Tomonori Koda Taichi Nishio Akihiro Nishioka
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.63, no.1, pp.19-22, 2016 (Released:2016-02-20)
参考文献数
11
被引用文献数
1

We examined a method to produce bread from crystalline rice flour without using thickening agents such as gluten, polysaccharide thickening, and amorphous rice flour. Rice grains were pulverized by a jet mill to produce flour. Samples of rice flours of various particle size distributions were prepared by using a size shifter. The degree of starch damage and the dynamic viscoelasticity of rice batter were measured in this work. We also baked bread of the flour of each size distribution to study processability for making bread. The batter made by the pulverized flour of rice particle size ranging from 75 to 106 μm had the highest expansion ratio and a good processability for baking breads compared to other particle size batters. The rice bread with high expansion ratio was produced by controlling particle size of crystalline rice flour without using thickening agents.
著者
Yu Teshigahara Ikuko Kakizaki Wataru Hirao Kanji Tanaka Ryoki Takahashi
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.67, no.2, pp.63-66, 2020-05-20 (Released:2020-05-20)
参考文献数
17

Human urinary trypsin inhibitor (UTI) is a proteoglycan composed of one core protein covalently linked to one glycosaminoglycan, which is a low sulfated chondroitin 4-sulfate. It is used as an anti-inflammatory medicine based on the protease inhibitory activity of the core protein. However, functions of the chondroitin sulfate have not been clarified. Recently, we succeeded in remodeling the UTI chondroitin sulfate to hyaluronan to create hyaluronan hybrid UTI, without changing the core protein. Here, we investigated the effect of the remodeled chondroitin sulfate on the activities of serine proteases. Native UTI showed stronger protease inhibitory activity than hyaluronan hybrid UTI or hydrolyzed glycosaminoglycan UTI. Chondroitin 4-sulfate chains with a small peptide derived from the native UTI did not show any protease inhibitory activity. These results suggest that the chondroitin sulfate chain linked covalently to core protein enhances protease inhibitor activity of UTI although the chondroitin sulfate chain itself does not.
著者
Masakazu Ike Ken Tokuyasu
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-2019_0019, (Released:2020-02-19)

The aim of this study was to investigate the effect of pH control by CO2 pressurization on the enzymatic hydrolysis of herbaceous feedstock in the calcium capturing by carbonation (CaCCO) process for fermentable sugar production. The pH of the slurry of 5% (w/w) Ca(OH)2-pretreated/CO2-neutralized rice straw could be controlled between 5.70 and 6.38 at 50 °C by changing the CO2 partial pressure (pCO2) from 0.1 to 1.0 MPa. A mixture of fungal enzyme preparations, namely, Trichoderma reesei cellulases/hemicellulases and Aspergillus niger β-glucosidase, indicated that pH 5.5–6.0 is optimal for solubilizing sugars from Ca(OH)2-pretreated rice straw. Enzymatic saccharification of pretreated rice straw under various pCO2 conditions revealed that the highest soluble sugar yields were obtained at pCO2 0.4 MPa and over, which is consistent with the expected pH at the pCO2 without enzymes and demonstrates the effectiveness of pH control by CO2 pressurization.
著者
Kiyohiko Igarashi Satoshi Kaneko Motomitsu Kitaoka Masahiro Samejima
出版者
The Japanese Society of Applied Glycoscience
雑誌
Journal of Applied Glycoscience (ISSN:13447882)
巻号頁・発行日
vol.67, no.2, pp.51-57, 2020-05-20 (Released:2020-05-20)
参考文献数
40

Cellobiose dehydrogenase (CDH) is a flavocytochrome catalyzing oxidation of the reducing end of cellobiose and cellooligosaccharides, and has a key role in the degradation of cellulosic biomass by filamentous fungi. Here, we use a lineup of glucose/xylose-mixed β-1,4-linked disaccharides and trisaccharides, enzymatically synthesized by means of the reverse reaction of cellobiose phosphorylase and cellodextrin phosphorylase, to investigate the substrate recognition of CDH. We found that CDH utilizes β-D-xylopyranosyl-(1→4)-D-glucopyranose (Xyl-Glc) as an electron donor with similar Km and kcat values to cellobiose. β-D-Glucopyranosyl-(1→4)-D-xylopyranose (Glc-Xyl) shows a higher Km value, while xylobiose does not serve as a substrate. Trisaccharides show similar behavior; i.e., trisaccharides with cellobiose and Xyl-Glc units at the reducing end show similar kinetics, while the enzyme was less active towards those with Glc-Xyl, and inactive towards those with xylobiose. We also use docking simulation to evaluate substrate recognition of the disaccharides, and we discuss possible molecular mechanisms of substrate recognition by CDH.
著者
Atsushi Kawano Kansuke Fukui Yuji Matsumoto Atsushi Terada Akihiro Tominaga Nozomi Nikaido Takashi Tonozuka Kazuhide Totani Nozomu Yasutake
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-2019_0015, (Released:2020-03-06)

According to whole-genome sequencing, Aspergillus niger produces multiple enzymes of glycoside hydrolases (GH) 31. Here we focus on a GH31 α-glucosidase, AgdB, from A. niger. AgdB has also previously been reported as being expressed in the yeast species, Pichia pastoris; while the recombinant enzyme (rAgdB) has been shown to catalyze tranglycosylation via a complex mechanism. We constructed an expression system for A. niger AgdB using Aspergillus nidulans. To better elucidate the complicated mechanism employed by AgdB for transglucosylation, we also established a method to quantify glucosidic linkages in the transglucosylation products using 2D NMR spectroscopy. Results from the enzyme activity analysis indicated that the optimum temperature was 65 °C and optimum pH range was 6.0–7.0. Further, the NMR results showed that when maltose or maltopentaose served as the substrate, α-1,2-, α-1,3-, and small amount of α-1,1-β-linked oligosaccharides are present throughout the transglucosylation products of AgdB. These results suggest that AgdB is an α-glucosidase that serves as a transglucosylase capable of effectively producing oligosaccharides with α-1,2-, α-1,3-glucosidic linkages.
著者
Hiromi Takada Takane Katayama Toshihiko Katoh
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-2019_0020, (Released:2020-02-19)

Ovomucin, a hen egg white protein, is characterized by its hydrogel-forming properties, high molecular weight, and extensive O-glycosylation with a high degree of sialylation. As a commonly used food ingredient, we explored whether ovomucin has an effect on the gut microbiota. O-Glycan analysis revealed that ovomucin contained core-1 and core-2 structures with heavy modification by N-acetylneuraminic acid and/or sulfate groups. Of the two mucin-degrading gut microbes we tested, Akkermansia muciniphila grew in medium containing ovomucin as a sole carbon source during a 24 h culture period, whereas Bifidobacterium bifidum did not. Both gut microbes, however, degraded ovomucin O-glycans and released monosaccharides into the culture supernatants in a species-dependent manner, as revealed by semi-quantified mass spectrometric analysis and anion exchange chromatography analysis. Our data suggest that ovomucin potentially affects the gut microbiota through O-glycan decomposition by gut microbes and degradant sugar sharing within the community.