著者

Tomoya Shintani Hirofumi Sakoguchi Akihide Yoshihara Ken Izumori Masashi Sato

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_0010, (Released:2019-10-24)

被引用文献数

7

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D-Allose (D-All), C-3 epimer of D-glucose, is a rare sugar known to suppress reactive oxygen species generation and prevent hypertension. We previously reported that D-allulose, a structural isomer of D-All, prolongs the lifespan of the nematode Caenorhabditis elegans. Thus, D-All was predicted to affect longevity. In this study, we provide the first empirical evidence that D-All extends the lifespan of C. elegans. Lifespan assays revealed that a lifespan extension was induced by 28 mM D-All. In particular, a lifespan extension of 23.8% was achieved (p < 0.0001). We further revealed that the effects of D-All on lifespan were dependent on the insulin gene daf-16 and the longevity gene sir-2.1, indicating a distinct mechanism from those of other hexoses, such as D-allulose, with previously reported antiaging effects.

著者

Junko Matsuki Tomoko Sasaki Koichi Yoza Junichi Sugiyama Hideo Maeda 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_0009, (Released:2019-10-24)

被引用文献数

2

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Rice-gel prepared by the following three steps: rice grain cooking, shearing of the cooked rice, and cooling for gel formation, is expected as a novel food ingredient for modification of various food products such as bread and noodles. To meet the demand for high-throughput systems for research and developments on the new rice gels, herein we established a mini-cooking system for preparation of rice gel samples from grains using a small-scale viscosity analyzer (Rapid Visco Analyzer; RVA). Polished rice grains (4 g) were cooked with 22 mL of water in a canister, and the paddle equipped in the canister was rotated at 2,000 rpm for 30 min (80 °C was used as a representative) to shear the cooked rice. The sheared paste was cooled to 10 °C at 160 rpm, and the initial gelation property was evaluated by viscosity analysis within the RVA. Alternatively, the sheared paste was transferred to an acrylic mold and kept at 4 °C for 0, 1, 3, and 5 days for determination of the hardness with a compression test. Compressive forces required to penetrate 20 % thickness for three tested rice cultivars were measured, and the trend of the value shifts during preservation is similar to the corresponding trend obtained in 300-g grain scale laboratory tests, whereas the individual values were halved in the former. This small cooking method could offer a useful assay system for a rapid evaluation in the breeding programs and in the high-throughput screening of additives for the modification of properties.

著者

Sangho Koh Seika Imamura Naoto Fujino Masahiro Mizuno Nobuaki Sato Satoshi Makishima Peter Biely Yoshihiko Amano

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_0007, (Released:2019-10-24)

被引用文献数

3

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The carbohydrate esterase family 1 (CE1) in CAZy contains acetylxylan esterases (AXEs) and feruloyl esterases (FAEs). Here we cloned a gene coding for an AXE belonging to CE1 from Irpex lacteus (IlAXE1). IlAXE1 was heterologously expressed in Pichia pastoris, and the recombinant enzyme was purified and characterized. IlAXE1 hydrolyzed p-nitrophenyl acetate, α-naphthyl acetate and 4-methylumbelliferyl acetate, however, it did not show any activity on ethyl ferulate and methyl p-coumarate. We also examined the activity on partially acetylated and feruloylated xylan extracted from corncob by hydrothermal reaction. Similarly, ferulic and p-coumaric acids were not liberated, and acetic acid was only detected in the reaction mixture. The results indicated that IlAXE1 is an acetylxylan esterase actually reacted to acetyl xylan. However, since IlAXE1 was unable to completely release acetic acid esterifying xylopyranosyl residues, it is assumed that acetyl groups exhibiting resistance to deacetylation by IlAXE1 are present in corn cob xylan.

著者

岡田 秀紀 川添 直樹 山森 昭 小野寺 秀一 塩見 徳夫

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.2, pp.143-148, 2008 (Released:2008-07-03)

参考文献数

25

被引用文献数

4 6

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植物エキス発酵飲料(以下FPE)は数十種類の野菜,果物を原料とし,sucroseの浸透圧を利用してエキスを抽出し約半年間,酵母および乳酸菌によって自然発酵させた褐色,粘ちょう性の飲料である.この飲料の投与によりラットの寿命延長効果が示唆されており,アルコール性胃粘膜障害抑制効果を有することやβ-(1,3)glucanが存在することをすでに報告している.FPE中に含まれるglucose,fructose以外の糖質の検索は,60%近い糖濃度の飲料であるため困難であったが,高感度に検出する方法を用いることにより微量に含まれるオリゴ糖類の検出が可能となり,その結果,数種の新規糖質および希少糖が見いだされた.FPEから活性炭クロマトグラフィー,amide-80カラムおよびODS-80Tsカラムを用いたHPLCにより十数種の糖類を単離した.これら糖質について酸加水分解による構成糖分析,MALDI-TOF-MS分析,完全メチル化メタノリゼートのGC分析,COSY,HSQC,HSQC-TOCSY,HMBC等の2次元NMR分析等により構造解析を行った.この結果,5種類の新規糖質を見いだし,それぞれO-β-D-fructopyranosyl-(2→6)-D-glucopyranose(Fp2-6G),O-β-D-fructopyranosyl-(2→6)-O-β-D-glucopyranosyl-(1→3)-D-glucopyranose,O-β-D-fructopyranosyl-(2→6)-O-[β-D-glucopyranosyl-(1→3)]-D-glucopyranose,1F-β-D-glucopyranosylsucrose,1F-β-D-galactopyranosylsucroseと決定した.これらの糖質は,発酵熟成中に生成された.新規糖質合成株のスクリーニングを行ったところ植物エキス発酵飲料の発酵熟成中の液から酵母5株(Y-1,-2,-3,-4,-5)を分離した.この株から調製した粗酵素液10 mLをpH 5.0の緩衝液に30%濃度になるよう溶解したglucose,fructose混液100 mLに加え,37°Cで加温した.5株についてFp2-6G合成活性を調べたところ,Y-1株粗酵素反応液中にFp2-6Gと同じ保持時間の糖が検出された.この反応液について各種クロマトグラフィーを行い糖を単離し,構造解析したところFp2-6Gであることが確認された.Y-1株粗酵素によるFp2-6Gの生成量は,上記反応系では非常に少なかったが,反応168時間後においても増加していた.また,基質濃度(glucose:fructose=1:1)の増加にともなって生成量が増加したが,70%濃度が上限であった.

著者

橋本 博之 山下 亜希子 藤田 孝輝 岡田 正通 森 茂治 園山 慶 北畑 寿美雄

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.51, no.2, pp.169-176, 2004 (Released:2008-03-24)

参考文献数

42

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Oligosaccharides with α-D-galactosidic linkages, especially the positional isomers of α-galactobiose (α-Gal 2), participate in such biological processes as immunity and pathogen-to-cell adhesion on the basis of molecular mechanisms for ligand-receptor interaction. α-Linked galactooligosaccharide (α-GOS) containing positional isomers of α-Gal 2 produced from galactose by the reverse reaction of α-galactosidase, is a potential food for the prevention of infections by pathogens, neutralization of toxins, and regulation of immune system. α-GOS (7.5 kg) was produced from galactose (18 kg; prepared from lactose hydrolyzate) by the reverse reaction of α-galactosidase from Aspergillus niger APC-9319. α-GOS contained 58% disaccharide, 28% trisaccharide and 14% oligosaccharides larger than trisaccharide. The disaccharide in α-GOS consisted largely of α-1,6-galactobiose (73%). α-GOS was stable at neutral and acidic pHs, and high temperatures. The sweetness of α-GOS was 25% of that of sucrose. The taste of α-GOS was mild and mellow. α-GOS reduced acid taste, bitterness, astringency, and harsh taste without spoiling the original taste in various fruit juices, and emphasized the original flavor of food materials in various cooked foods. α-GOS was not hydrolyzed in an in vitro digestion method. In oral tolerance tests of α-GOS, the blood glucose level did not change at all. α-GOS had a strong selective growth activity for Bifidobacterium sp. and Clostridium butyricum. An α-GOS intake in rats made the contents of lactate and n-butyrate in the cecum higher, and pH in the cecum lower than for a control intake. The viable count of Candida albicans in cecum and colon of mouse was decreased by an α-GOS intake more than by a raffinose intake. Therapeutic oral treatment with α-GOS had a potent inhibitory effect on adjuvant arthritis in Wister rats and on type II collagen-induced arthritis in DBA/1 J mice. Dietary α-GOS ameliorated allergic airway eosinophilia at least partly via post-absorptive mechanisms in Brown Norway rats.

著者

Hayashi Mari Kodama Momoko Nakamura Yasunori Fujita Naoko

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.62, no.2, pp.81-86, 2015

被引用文献数

16

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Starch is glucose polymer linked by α-1,4 and α-1,6 glucosidic bonds. The balance of activity between starch synthases (SSs) and branching enzymes (BEs) is important for formation of amylopectin structure. SSI and SSIIIa isozymes account for 60 and 30%, respectively, of soluble SS activity in developing rice endosperm. Complete loss of both SSI and SSIIIa activities induces sterility. By contrast, a double mutant (<i>ss1^L/ss3a</i>) generated by crossing the leaky <i>ss1</i> mutant, whose SS activity is approximately ca. 16% of the wild type, and the <i>ss3a</i> null mutant is fertile. Although there is only a significant residual SS activity in the developing endosperm of <i>ss1^L/ss3a</i>, the yield and growth of the double-mutant line is sufficient. We analyzed the amylopectin chain-length distribution, thermal and pasting properties, morphologies of starch granules and amyloplasts, and crystallinity of endosperm starch in <i>ss1^L/ss3a</i> and the parental mutant lines. The chain-length distribution pattern of <i>ss1^L/ss3a</i> was similar to that of <i>ss3a</i> and there was an additive effect of the reduction of SSI activity on the chain-length of amylopectin in the <i>ss3a</i> background. These changes in the amylopectin chain-length distribution were considered to increase the gelatinization temperature of the starch. The gelatinized starch viscosity of the double-mutant and <i>ss3a</i> lines was very low. Most <i>ss1^L/ss3a</i> starch granules were round-shaped, and the starch granular size was smaller than those of the parental mutant lines and the wild type. The starch crystallinity of <i>ss1^L/ss3a</i> was slightly reduced compared with that of the wild type.

著者

鈴木 綾子

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.46, no.1, pp.65-74, 1999-03-31 (Released:2010-06-28)

参考文献数

22

被引用文献数

1 2

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Starchy materials such as cereals, legumes, tubers, and rhizomes are served as foods through the appropriate processing of cooking, which causes the gelatinization of starch. The gelatinized starch is thermodynamically unstable and tends to retrograde during storage. The retrogradation generally decreases the quality of foods known as the staling of bread and the hardening of cooked rice. Therefore, how to control gelatinization and retrogradation is of prime concern of cereal chemists and technologists. I have been involved in this study for nearly 40 years. As early as 1961 we found that microwave heating was very efficient for the rapid cooking of rice, but the cooked rice rapidly hardened by the retrogradation of starch. This was improved by the addition of a small amount of Takaamylase in cooking. Root vegetables are well known for being unable to become soft through cooking even by continued heating after heating has been suspended for a while halfway through cooking. By a detailed analysis of the gelatinization of starch during cooking, this phenomenon was found to be caused by the enhancement of retrogradation of the partially gelatinized starch by cooling. Furthermore, it was found that the heat-stable materials, including various minerals, enhanced the retrogradation. The relationship between structures and functions was investigated on various kinds of starch such as nagaimo (yam), lotus, arrowhead, taro, bracken, and tapioca used in confectioneries. It was found that starches having a high tendency to retrograde had amylopectin with long chain-length and smaller amylose molecules. For example, tapioca starch showed the lowest retrogradation tendency, and this appeared to be due to the short chain length of amylopectin and large amylose molecules, besides thee low amylose content. The relatively higher retrogradation tendency of potato starch seemed to be due to the long chain length of amylopectin. A clear-cut relationship was found between the phosphate content and the pasting viscosity in potato starch that the higher level of phosphorus gave the higher-pasting viscosities. Kuzu amylopectin showed a relatively low retrogradation tendency because of the medium chain length of amylopectin, but kuzu amylose had a high retrograding tendency because of small molecules. Bracken amylopectin with a similar chain length showed a similar retrograding tendency to that of kuzu. Some taro starches showed similar structures and properties to tapioca starch, and they also had low levels of amylose. The starches found in vegetables used in cuisine on New Year's Day have low retrograding tendencies. Therefore they are suitable for use as preservable foods. Amylose molecules are slightly branched molecules on average, and the branches are mostly short chains, but the function of side chains has not been investigated. We attempted to clarify this function by means of a model experiment on molecules that had incorporated small amounts of maltosyl side chains into linear chains by the reverse action of isoamylase. The results clearly showed that these small amounts of maltose side chains affected a decrease in retrograding tendency.

著者

大島 久華 木村 功 木村 義雄 田島 茂行 何森 健

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.52, no.3, pp.261-265, 2005

被引用文献数

1

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<i>Aspergillus sojae</i>の液体培養液からエキソ-1,5-&alpha;-L-アラビナナーゼを電気泳動的に均一な標品として精製した. 精製酵素標品の分子質量は, ドデシル硫酸ナトリウム-ポリアクリルアミドゲル電気泳動 (SDS-PAGE) によって41kDa, ゲル濾過クロマトグラフィーによって43 kDaと決定された. 本酵素の等電点は3.7であった. 本エキソ-アラビナナーゼ活性は, カルボキシメチル-直鎖アラビナンに対し, 50℃, pH 5.0で作用させることで最大となった. 活性はpH 6.0から8.0, 45℃まで安定であった. 精製酵素標品の活性はAg⁺ (1 mM) およびCr²⁺ (1 mM) によって強く阻害され, SDS (5 mM) の添加により促進された. 1,5-アラビナンに対する<i>K</i>_m値は5.8mg/mLとなった. 本精製酵素標品のN末端アミノ酸25残基は, <i>Penicillium chrysogenum</i>のそれと69%という高い相同性を示した. 精製酵素標品をビート由来の1,5-アラビナンに作用させた場合のおもな生産物は, アラビノビオースであり, 反応溶液中にアラビノースの遊離は認められなかった.

著者

Naoko Crofts Ayaka Itoh Misato Abe Satoko Miura Naoko F. Oitome Jinsong Bao Naoko Fujita

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-2018_005, (Released:2018-12-07)

被引用文献数

16

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Extra-long chains (ELC) of amylopectin in rice endosperm are synthesized by granule-bound starch synthase I encoded by the Waxy (Wx) gene, which primarily synthesizes amylose. Previous studies showed that single nucleotide polymorphisms (SNP) in intron 1 and exon 6 of the Wx gene influences ELC amount. However, whether these SNPs are conserved among rice cultivars and if any other SNPs are present in the Wx gene remained unknown. Here, we sequenced the Wx gene from 17 rice cultivars with S or L-type amylopectin, including those with known ELC content and those originating in China with unique starch properties, as well as typical japonica and indica cultivars. In addition to the two SNPs described above, an additional SNP correlating with ELC content was found in exon 10. Low ELC cultivars (<3.0 %) had thymine at the splicing donor site of intron 1, Tyr224 in exon 6, and Pro415 in exon 10. Cultivars with moderate ELC content (4.1–6.9 %) had guanine at the splicing donor site of intron 1, Ser224 in exon 6, and Pro415 in exon 10. Cultivars with high ELC content (7.7–13.9 %) had guanine at the splicing donor site of intron 1, Tyr224 in exon 6, and Ser415 in exon 10. The chain length distribution pattern of amylopectin was correlated with the amounts of SSIIa found in starch granules and gelatinization temperature, but not with ELC content. The combinations of SNPs in the Wx gene found in this study may provide useful information for screening specific cultivars with different ELC content.

著者

Hideyuki Takahashi Chiharu Yoshida Takumi Takeda

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-2018_0007, (Released:2018-12-07)

被引用文献数

5

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Sugars are one of the most important factors determining the taste and texture of asparagus (Asparagus officinalis). In this study, we quantified soluble and insoluble sugars in asparagus spears grown in four different agricultural fields. We measured soil chemical properties in each of the fields, and further investigated the relationship between sugar contents in the spears and soil chemical properties. We found a possible relationship between the contents of glucose and fructose and values of cation exchange capacity, available phosphoric acid, and exchangeable calcium and magnesium in the soil. These findings will be useful information for improving asparagus quality.

著者

Seo Eun-Seong Kandra Lili Gyémánt Gyöngyi Janecek Štefan Haser Richard Aghajari Nushin Hachem Maher Abou Svensson Birte Andersen Joakim M. Nielsen Morten M. Vester-Christensen Malene B. Christiansen Camilla Jensen Johanne M. Mótyán Janos A. Glaring Mikkel A. Blennow Andreas

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.2, pp.157-162, 2010

被引用文献数

3

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Two carbohydrate binding surface sites (SBSs) on barley &alpha;-amylase 1 (AMY1) of glycoside hydrolase family 13 (GH13) displayed synergy in interactions with starch granules, thus being pivotal for hydrolysis of supramolecular substrates. Mutational analysis showed that SBS1 is more critical for the conversion of starch granules, while SBS2 has higher affinity than SBS1 for &beta;-cyclodextrin (&beta;-CD). Noticeably, the binding preference of &beta;-CD to SBS2 differed distinctly from that of maltooligosaccharides to the catalytic nucleophile mutant D180A AMY1. Binding energy maps at subsites -8 through +4 of the active site indicated remarkably elevated affinity due to the Y380A mutation at SBS2. The high-yield AMY2 expression variant A42P, made it possible to show that Tyr378&mdash;corresponding to Tyr380 in AMY1&mdash;has a role in interactions with starch granules, but not in &beta;-CD binding. Besides SBSs, dedicated starch binding domains (SBDs) mediate binding to starch granules. SBDs are currently categorised into 9 carbohydrate binding module (CBM) families. A novel CBM20 subfamily encountered in regulatory enzymes possesses characteristically low affinity for &beta;-CD. Although &alpha;-amylase is essential for starch mobilisation in germinating barley seeds, efficient degradation requires the concerted action of &alpha;-amylase, &beta;-amylase, limit dextrinase (LD) and possibly &alpha;-glucosidase. Limit dextrinase (LD) is encoded by a single gene and represents the sole debranching activity during germination. Recent expression of functional LD in <i>Pichia pastoris</i> makes biochemical and biophysical characterisation of this GH13 enzyme possible. An endogenous limit dextrinase inhibitor was cloned and produced recombinantly and demonstrated to have sub-nanomolar affinity for LD.

著者

Haruka Yagi Ryo Takehara Aika Tamaki Koji Teramoto Sosyu Tsutsui 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-2018_0008, (Released:2018-11-05)

被引用文献数

14

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We functionally characterized the GH10 xylanase (SoXyn10A) and the GH11 xylanase (SoXyn11B) derived from the actinomycete Streptomyces olivaceoviridis E-86. Each enzyme exhibited differences in the produced reducing power upon degradation of xylan substrates. SoXyn10A produced higher reducing power than SoXyn11B. Gel filtration of the hydrolysates generated by both enzymes revealed that the original substrate was completely decomposed. Enzyme mixtures of SoXyn10A and SoXyn11B produced the same level of reducing power as SoXyn10A alone. These observations were in good agreement with the composition of the hydrolysis products. The hydrolysis products derived from the incubation of soluble birchwood xylan with a mixture of SoXyn10A and SoXyn11B produced the same products as SoXyn10A alone with similar compositions. Furthermore, the addition of SoXyn10A following SoXyn11B-mediated digestion of xylan produced the same products as SoXyn10A alone with similar compositions. Thus, it was hypothesized that SoXyn10A could degrade xylans to a smaller size than SoXyn11B. In contrast to the soluble xylans as the substrate, the produced reducing power generated by both enzymes was not significantly different when pretreated milled bagasses were used as substrates. Quantification of the pentose content in the milled bagasse residues after the enzyme digestions revealed that SoXyn11B hydrolyzed xylans in pretreated milled bagasses much more efficiently than SoXyn10A. These data suggested that the GH10 xylanases can degrade soluble xylans smaller than the GH11 xylanases. However, the GH11 xylanases may be more efficient at catalyzing xylan degradation in natural environments (e.g. biomass) where xylans interact with celluloses and lignins.

著者

Di Guan Rui Zhao Yuan Li Yoshikiyo Sakakibara 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-2018_0006, (Released:2018-11-05)

被引用文献数

5

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Novel bioreactor beads for simultaneous saccharification and fermentation (SSF) of lime-pretreated rice straw (RS) into ethanol were prepared. Genetically modified Saccharomyces cerevisiae cells expressing genes encoding xylose reductase, xylitol dehydrogenase, and xylulokinase were immobilized in calcium alginate beads containing inorganic lightweight filler particles to reduce specific gravity. For SSF experiments, the beads were floated in slurry composed of lime-pretreated RS and enzymes and incubated under CO2 atmosphere to reduce the pH for saccharification and fermentation. Following this reaction, beads were readily picked up from the upper part of the slurry and were directly transferred to the next vessel with slurry. After 240 h of incubation, ethanol production by the beads was equivalent to that by free cells, a trend that was repeated in nine additional runs, with slightly improved ethanol yields. Slurry with pre-saccharified lime-pretreated RS was subjected to SSF with floating beads for 168 h. Although higher cell concentrations in beads resulted in more rapid initial ethanol production rates, with negligible diauxic behavior for glucose and xylose utilization, no improvement in the ethanol yield was observed. A fermentor-scale SSF experiment with floating beads was successfully performed twice, with repeated use of the beads, resulting in the production of 40.0 and 39.7 g/L ethanol. There was no decomposition of the beads during agitation at 60 rpm. Thus, this bioreactor enables reuse of yeast cells for efficient ethanol production by SSF of lignocellulosic feedstock, without the need for instruments for centrifugation or filtration of whole slurry.

著者

Kenji Yamagishi Masakazu Ike Di Guan 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-2018_0003, (Released:2018-11-05)

被引用文献数

7

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Generally, Ca(OH)2 pretreatment of lignocellulosics for fermentable sugar recovery requires a subsequent washing step for calcium removal and pH control for optimized saccharification. However, washing Ca(OH)2-pretreated feedstock with water is considered problematic because of the low solubility of Ca(OH)2 and its adsorption to biomass. In this study, we estimated the availability of carbonated water for calcium removal from the slurry of Ca(OH)2-pretreated rice straw (RS). We tested two kinds of countercurrent washing sequences, four washings exclusively with water (W4) and two washings with water and subsequent two washings with carbonated water (W2C2). The ratios of calcium removal from pretreatment slurry after washing were 64.2 % for the W4 process and 92.1 % for the W2C2 process. In the W2C2 process, 49 % of the initially added calcium was recovered as CaO by calcination. In enzymatic saccharification tests under a CO2 atmosphere at 1.5 atm, in terms of recovery of both glucose and xylose, pretreated, feedstock washed through the W2C2 process surpassed that washed through the W4 process, which could be attributed to the pH difference during saccharification: 5.6 in the W2C2 process versus 6.3 in the W4 process. Additionally, under an unpressurized CO2 atmosphere at 1 atm, the feedstock washed through the W2C2 process released 78.5 % of total glucose residues and 90.0 % of total xylose residues. Thus, efficient removal of calcium from pretreatment slurry would lead to not only the recovery of added calcium but also the proposal of a new, simple saccharification system to be used under an unpressurized CO2 atmosphere condition.

著者

Kazuhiro Chiku Mami Wada Haruka Atsuji Arisa Hosonuma Mitsuru Yoshida Hiroshi Ono 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

pp.jag.JAG-2018_0002, (Released:2018-11-05)

被引用文献数

6

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We evaluated the stabilities of kojibiose and sophorose when heated under neutral pH conditions. Kojibiose and sophorose epimerized at the C-2 position of glucose on the reducing end, resulting in the production of 2-O-α-D-glucopyranosyl-D-mannose and 2-O-β-D-glucopyranosyl-D-mannose, respectively. Under weak alkaline conditions, kojibiose was decomposed due to heating into its mono-dehydrated derivatives, including 3-deoxy-2,3-unsaturated compounds and bicyclic 3,6-anhydro compounds. Following these experiments, we propose a kinetic model for the epimerization and decomposition of kojibiose and sophorose by heat treatment under neutral pH and alkaline conditions. The proposed model shows a good fit with the experimental data collected in this study. The rate constants of a reversible epimerization of kojibiose at pH 7.5 and 90 °C were (1.6 ± 0.1) × 10−5 s−1 and (3.2 ± 0.2) × 10−5 s−1 for the forward and reverse reactions, respectively, and were almost identical to those [(1.5 ± 0.1) × 10−5 s−1 and (3.5 ± 0.4) × 10−5 s−1] of sophorose. The rate constant of the decomposition reaction for kojibiose was (4.7 ± 1.1) × 10−7 s−1 whereas that for sophorose [(3.7 ± 0.2) × 10−6 s−1] was about ten times higher. The epimerization reaction was not significantly affected by the variation in the buffer except for a borate buffer, and depended instead upon the pH value (concentration of hydroxide ions), indicating that epimerization occurred as a function of the hydroxide ion. These instabilities are an extension of the neutral pH conditions for keto-enol tautomerization that are often observed under strong alkaline conditions.

著者

栗波 哲 杉本 雅俊

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.54, no.1, pp.23-26, 2007 (Released:2007-03-08)

参考文献数

6

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モチ米粒の湿熱処理が糊化温度,色調および餅生地の硬度に及ぼす影響を検討した.北海道産ハクチョウモチを用い,米水分含量を15.2および20.3%に調整し,限定された水分存在下での加熱(密閉系)の場合と相対湿度100%での加熱(開放系)の場合の両方で湿熱処理を実施した.湿熱処理によって,モチ米の糊化開始温度は高温側に移動し,餅生地の硬化は促進した.糊化開始温度の高温側への移動は湿熱処理方法,加熱温度,時間および米水分含量の影響を受けた.有効積算温度〔(処理温度-80℃)×処理時間(h)〕と糊化開始温度の増加との間に密接な関係があることが認められた.有効積算温度が密閉系では120(℃·h),開放系では60(℃·h)で糊化開始温度はほぼ一定となった.湿熱処理によってモチ米の白色度は低下したが,とう精歩合を88%にすることにより白色度は改善された.

著者

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.64, no.4, pp.99-107, 2017-11-20 (Released:2017-11-20)

参考文献数

18

被引用文献数

8

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3-Keto-levoglucosan (3ketoLG) has been postulated to be the product of a reaction catalyzed by levoglucosan dehydrogenase (LGDH), a bacterial enzyme involved in the metabolism of levoglucosan (LG). To investigate the LG metabolic pathway catalyzed by LGDH, 3ketoLG is needed. However, 3ketoLG has not been successfully isolated from the LGDH reaction. This study investigated the ability of pyranose oxidase to convert LG into 3ketoLG by oxidizing the C3 hydroxyl group. During the oxidation of LG, 3ketoLG was spontaneously crystallized in the reaction mixture. Starting with 500 mM LG, the isolation yield of 3ketoLG was 80 %. Nuclear magnetic resonance analyses revealed that a part of 3ketoLG dimerized in aqueous solution, explaining its poor solubility. Even under normal conditions, 3ketoLG was unstable in aqueous solution, with a half-life of 16 h at pH 7.0 and 30 °C. The decomposition proceeded through β-elimination of the C–O bonds at both C1 and C5, as evidenced by decomposition products. This instability explains the difficulty in obtaining 3ketoLG via the LGDH reaction.

著者

袴田 航 室井 誠 西尾 俊幸 奥 忠武 高月 昭 長田 裕之 福原 潔 奥田 晴宏 栗原 正明

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.53, no.2, pp.149-154, 2006-04-20

参考文献数

20

被引用文献数

9

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現在,新H5N1型インフルエンザやSARSなど続々と出現する新興ウイルス感染症や鳥インフルエンザのヒトへの伝播等,新興ウイルス感染症は人類の脅威となっている.しかし,ウイルス感染症に対する有効な薬剤の開発は,細菌感染症の抗生物質に比べ遅れている.そこで,ウイルス共通の感染機序に基づいた薬剤の開発が重要と考え,外被を有する多くのウイルスの感染・増殖には複合型のN-結合型糖鎖が関与している知見を基にして,小胞体N-結合型糖鎖プロセシング酵素を標的酵素とした分子標的薬の開発を目指して研究を行っている.分子標的薬の開発には,標的酵素である糖鎖プロセシング酵素の基質特異性の解明が必要であると考えた.そこで,合成プローブを用いてN-結合型糖鎖プロセシングの第1段階を担うプロセシンググルコシダーゼI (EC 3.2.1.106)と第2段階を担うプロセシンググルコシダーゼII (EC 3.2.1.84)のグリコンおよびアグリコン特異性を調べ,&alpha;-グルコシダーゼ (EC 3.2.1.20, GH13 and GH31) のそれと比較した.その結果,グルコシダーゼIのグリコン特性はGH13 &alpha;-グルコシダーゼと,グルコシダーゼIIのグリコン特性はGH31 &alpha;-グルコシダーゼと同様であった.またグルコシダーゼIとグルコシダーゼIIのアグリコン認識は同様であり,GH13およびGH31 &alpha;-グルコシダーゼとは異なっていた.そこで,プロセシンググルコシダーゼIおよびIIを標的として,酵素阻害剤候補化合物の設計と合成を行った.これら候補化合物の<i>in vitro</i>酵素阻害活性と細胞レベルでのウイルス外被糖タンパク質の合成・成熟・転送阻害およびプラーク法による感染性ウイルス数の測定を行った.その結果,<i>in vitro</i>においてヘプチトール誘導体,スルフォニル誘導体の一部にIC<small>50</small>約50 &mu;Mの阻害活性を,カテキン誘導体の一部にIC<small>50</small> 0.9 &mu;Mの強力な阻害活性を見いだした.さらに,細胞レベルではカテキン誘導体の一部にプロセシンググルコシダーゼ阻害を作用点とするとみられる比較的強い抗ウイルス活性を見いだした.今後,ウイルス外被糖タンパク質の糖鎖構造解析等により詳細な作用機序の解明を行う予定である.

著者

Hayashi Mari Kodama Momoko Nakamura Yasunori Fujita Naoko

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

2015

被引用文献数

16

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Starch is glucose polymer linked by α-1,4 and α-1,6 glucosidic bonds. The balance of activity between starch synthases (SSs) and branching enzymes (BEs) is important for formation of amylopectin structure. SSI and SSIIIa isozymes account for 60% and 30%, respectively, of soluble SS activity in developing rice endosperm. Complete loss of both SSI and SSIIIa activities induces sterility. By contrast, a double mutant (<i>ss1^L/ss3a</i>) generated by crossing the leaky <i>ss1</i> mutant, whose SS activity is approximately ca. 16% of the wild type, and the <i>ss3a</i> null mutant is fertile. Although there is only a significant residual SS activity in the developing endosperm of <i>ss1^L/ss3a</i>, the yield and growth of the double-mutant line is sufficient. We analyzed the amylopectin chain-length distribution, thermal and pasting properties, morphologies of starch granules and amyloplasts, and crystallinity of endosperm starch in <i>ss1^L/ss3a</i> and the parental mutant lines. The chain-length distribution pattern of <i>ss1^L/ss3a</i> was similar to that of <i>ss3a</i> and there was an additive effect of the reduction of SSI activity on the chain-length of amylopectin in the <i>ss3a</i> background. These changes in the amylopectin chain-length distribution were considered to increase the gelatinization temperature of the starch. The gelatinized starch viscosity of the double-mutant and <i>ss3a</i> lines was very low. Most <i>ss1^L/ss3a</i> starch granules were round-shaped, and the starch granular size was smaller than those of the parental mutant lines and the wild type. The starch crystallinity of <i>ss1^L/ss3a</i> was slightly reduced compared with that of the wild type.

著者

Yuki Sasaki Nami Togo Kanefumi Kitahara Kiyotaka Fujita

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.23-30, 2018-05-20 (Released:2018-05-20)

参考文献数

27

被引用文献数

5

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β-L-Arabinopyranosidases are classified into the glycoside hydrolase family 27 (GH27) and GH97, but not into GH36. In this study, we first characterized the GH36 β-L-arabinopyranosidase BAD_1528 from Bifidobacterium adolescentis JCM1275. The recombinant BAD_1528 expressed in Escherichia coli had a hydrolytic activity toward p-nitrophenyl (pNP)-β-L-arabinopyranoside (Arap) and a weak activity toward pNP-α-D-galactopyranoside (Gal). The enzyme liberated L-arabinose efficiently not from any oligosaccharides or polysaccharides containing Arap-β1,3-linkages, but from the disaccharide Arap-β1,3-L-arabinose. However, we were unable to confirm the in vitro fermentability of Arap-β1,3-Ara in B. adolescentis strains. The enzyme also had a transglycosylation activity toward 1-alkanols and saccharides as acceptors.