研究者詳細 - 今村　維克

論文 - 今村　維克

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Characteristics of Sugar Surfactants in Stabilizing Proteins During Freeze-Thawing and Freeze-Drying 査読

Koreyoshi Imamura, Katsuyuki Murai, Tamayo Korehisa, Noriyuki Shimizu, Ryo Yamahira, Tsutashi Matsuura, Hiroko Tada, Hiroyuki Imanaka, Naoyuki Ishida, Kazuhiro Nakanishi

JOURNAL OF PHARMACEUTICAL SCIENCES 103 ( 6 ) 1628 - 1637 2014年6月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Sugar surfactants with different alkyl chain lengths and sugar head groups were compared for their protein-stabilizing effect during freeze-thawing and freeze-drying. Six enzymes, different in terms of tolerance against inactivation because of freeze-thawing and freeze-drying, were used as model proteins. The enzyme activities that remained after freeze-thawing and freeze-drying in the presence of a sugar surfactant were measured for different types and concentrations of sugar surfactants. Sugar surfactants stabilized all of the tested enzymes both during freeze-thawing and freeze-drying, and a one or two order higher amount of added sugar surfactant was required for achieving protein stabilization during freeze-drying than for the cryoprotection. The comprehensive comparison showed that the C10-C12 esters of sucrose or trehalose were the most effective through the freeze-drying process: the remaining enzyme activities after freeze-thawing and freeze-drying increased at the sugar ester concentrations of 1-10 and 10-100 M, respectively, and increased to a greater extent than for the other surfactants at higher concentrations. Results also indicate that, when a decent amount of sugar was also added, the protein-stabilizing effect of a small amount of sugar ester through the freeze-drying process could be enhanced. (c) 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci

添付ファイル： P1SugSF-pub.pdf

DOI： 10.1002/jps.23988

糖界面活性剤を用いたタンパク質の安定化

今村維克

オレオサイエンス 14 ( 11 ) 487 - 493 2014年

記述言語：日本語出版者・発行元：公益社団法人日本油化学会

<p>タンパク質は食品や医薬品分野で不可欠な材料であるが，非生理的環境下では容易に変性し，その優れた生理活性を失ってしまう場合が多い。そのためタンパク質の安定化技術，とりわけ安定化物質の探索が以前より行われてきた。一方，糖を親水基とする糖界面活性剤は食品添加物として広範に利用されているが，タンパク質の変性を抑制する作用も有している。本稿では，タンパク質が曝される各状態・操作における変性機構とともに，糖界面活性剤のタンパク質安定化における有効性について述べる。特に凍結および凍結乾燥過程におけるタンパク質安定化作用について，種々の糖界面活性剤が各種酵素の活性保持に対する影響を調査し，糖界面活性剤の極性基の構造やアルキル鎖長，およびアルキル鎖との結合形態が凍結および凍結乾燥時におけるタンパク質安定化作用に及ぼす影響について考察を加えた。</p>

DOI： 10.5650/oleoscience.14.487

その他リンク： http://search.jamas.or.jp/link/ui/2015030450

水中の疎水化シリカ表面間に働く短距離性疎水性引力に及ぼす表面の疎水性の影響

曽我友平, 今中洋行, 今村維克, 石田尚之

粉体工学会誌 51 ( 5 ) 343 - 348 2014年

記述言語：英語出版者・発行元：一般社団法人粉体工学会

The interaction forces between silanated silica surfaces with no nanobubbles were measured using colloidal probe atomic force microscopy (AFM). To obtain hydrophobic surfaces without nanobubbles, an aqueous solution was introduced between the surfaces following an exchange process involving several solvents. In the obtained approachingforce curves, an attractive force was observed from a distance of 10～20 nm, which is an additional attractive force stronger than typical van der Waals attractions. When the surface hydrophobicity decreased, the range of this attraction decreased slightly ; the attraction disappeared when the surface contact angle was below 90°。. In contrast, measurements in the water-ethanol mixtures revealed that the attraction persisted even when the contact angle was well below 90°。. The possible origin of this force was discussed on the basis of the obtained results.

DOI： 10.4164/sptj.51.343

2P078 新規金表面親和性ペプチドの同定及びタンパク質固定化への応用(01D. 蛋白質:機能,ポスター,第52回日本生物物理学会年会(2014年度))

Shigemori Yojiro, Yoshida Kaori, Imamura Koreyoshi, Takahashi Yuichiro, Imanaka Hiroyuki

生物物理 54 ( 1 ) S207 2014年

2P085 CS複合体形成をモデルとした高感度ペプチド-タンパク質間相互作用検出系のデザイン(01F. 蛋白質:蛋白質工学/進化工学,ポスター,第52回日本生物物理学会年会(2014年度))

Matsushita Runa, Ishida Naoyuki, Imamura Koreyoshi, Imanaka Hiroyuki

生物物理 54 ( 1 ) S209 2014年

Improving the physical stability of freeze-dried amorphous sugar matrices by compression at several hundreds MPa 査読

Ryo Kagotani, Kohshi Kinugawa, Mayo Nomura, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

JOURNAL OF PHARMACEUTICAL SCIENCES 102 ( 7 ) 2187 - 2197 2013年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Amorphous matrices, composed of sugars, are markedly plasticized by moisture uptake, which results in physical instability. Our previous studies, in the compression pressure range 443 MPa, indicated that when a matrix is compressed, the amount of sorbed water at given relative humidities (RHs) decreases, whereas the glass transition temperature (Tg) remains constant. Herein, the effect of higher compression pressures than those used previously was explored to investigate the feasibility of using compression to improve the physical stability of amorphous sugar matrix against water uptake and subsequent collapse. Amorphous sugar samples were prepared by freeze-drying and then compressed at 0-665 MPa, followed by rehumidification at given RHs. The physical stability of the amorphous sugar sample was evaluated by measuring Tg and crystallization temperature (Tcry). The amounts of sorbed water, different in the interaction state, were determined using an FTIR technique. It was found that the compression at pressures of 443 MPa decreased the amount of sorbed water, which is a major factor in plasticization and crystallization, and thus markedly increased the Tg and Tcry relative to that for the uncompressed sample. Hence, the compression at several hundreds MPa appears to be feasible for improving the physical stability of amorphous sugar matrix. (c) 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:2187-2197, 2013

DOI： 10.1002/jps.23568

Improvement on the freeze-thaw stability of corn starch gel by the polysaccharide from leaves of Corchorus olitorius L. 査読

Eiji Yamazaki, Toru Sago, Yoshiaki Kasubuchi, Kazuhito Imamura, Toshio Matsuoka, Osamu Kurita, Hironobu Nambu, Yasuki Matsumura

Carbohydrate Polymers 94 ( 1 ) 555 - 560 2013年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

Effect of the polysaccharide from leaves of Corchorus olitorius L. (PLC) on the freeze-thaw (FT) stability of corn starch gel was studied. PLC was incorporated into the starch gel at 0.7% and total solid was adjusted to 6.0%. The syneresis was measured by the centrifugal-filtration method and, as a result, addition of PLC reduced effectively the syneresis of the starch gel even after 5 FT cycles, which was less than one third that of the normal starch gel. The rheological changes of the starch/PLC gel during the FT treatments were evaluated while the gel remained on the rheometer plate. The starch/PLC gel had less significant changes in the rheological parameters during the FT cycles than starch/guar gum or xanthan gum gel systems. SEM images showed that PLC stabilized the gel matrix surrounding pores, which would contribute to both a lower syneresis production and a higher stability in the rheological behavior at FT. © 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbpol.2013.01.079

Characteristics of amorphous matrices composed of different types of sugars in encapsulating emulsion oil droplets during freeze-drying 査読

Koreyoshi Imamura, Yoshifumi Kimura, Shota Nakayama, Miki Sayuri, Seiji Ogawa, Tatsuya Hoshino, Jun Oshitani, Takashi Kobayashi, Shuji Adachi, Tsutashi Matsuura, Hiroyuki Imanaka, Naoyuki Ishida, Kazuhiro Nakanishi

FOOD RESEARCH INTERNATIONAL 51 ( 1 ) 201 - 207 2013年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The encapsulation of emulsion oil droplets by amorphous sugar matrices, formed by freeze-drying, was investigated, with a focus on the influence of the type of sugar. An oil-in-water emulsion, comprised of linoleic acid methyl ester (LME) and sucrose monolaurate (SML) as an oil phase and surfactant, respectively, were freeze-dried in the presence of different types of sugars. LME-droplet encapsulation during and after freeze-drying were evaluated by FTIR analysis. The loss of LME largely occurred in the early stage of freeze-drying. The size distribution of the encapsulated LME droplets remained unchanged before and after freeze-drying in most cases. The encapsulated fractions of LME droplets could be correlated with the glass transition temperature of the sugars in the fully hydrated state (T-g*), and the existence of an optimum T-g* value for the sugar matrix was predicted. The encapsulation ability of an amorphous sugar matrix was maximized when mono- and polysaccharide were combined so as to give a value for T-g* of approximately -50 degrees C, although, individually, mono- and polysaccharides were quite poor for oil droplet encapsulation. These findings suggest that the structural flexibility of the amorphous sugar matrix is a major determinant in oil droplet encapsulation by an amorphous sugar matrix during freeze-drying. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodres.2012.12.010

On the preparation of indoxyl red from indican and some new characteristics 査読

Jingyuan Song, Mizuki Kitamatsu, Koreyoshi Imamura, Hitoshi Ohmori, Kouji Watanabe, Kazuhiro Nakanishi

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 23 ( 3 ) 627 - 629 2013年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

An indole compound with a strong purple-red color was produced by boiling a solution of indican under acidic conditions and purified by chromatographies on DEAE-650S Toyopearl TSK-gel and silica-gel columns. The purple-red compound purified was identified as indoxyl red, on the basis of FAB Mass, C-13 NMR, H-1 NMR, UV-visible spectra, and IR spectra. Although indoxyl red was first synthesized by Seidel(9) 70 years ago, very little information has been available on its characteristics. We repot here that the compound was purple-red colored at acidic pH and green at pH 13, and showed antiproliferative and cytotoxic activities to the mouse B cell lymphoma cell line NSF202. (c) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2012.12.006

The discoidin domain of Bacillus circulans β-galactosidase plays an essential role in repressing galactooligosaccharide production. 査読

Song J, Imanaka H, Imamura K, Minoda M, Yamaguchi S, Nakanishi K

Bioscience, biotechnology, and biochemistry 77 ( 1 ) 73 - 79 2013年1月

Impact of compression, physical aging, and freezing rate on the crystallization characteristics of an amorphous sugar matrix 査読

Koreyoshi Imamura, Kohshi Kinugawa, Ryo Kagotani, Mayo Nomura, Kazuhiro Nakanishi

JOURNAL OF FOOD ENGINEERING 112 ( 4 ) 313 - 318 2012年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCI LTD

Amorphous matrices made up of sugar molecules, are frequently used in food and pharmaceutical industries. A drawback to their use is that they are susceptible to collapse, as a result of water uptake and an increase in temperature and subsequently crystallize. Herein, the crystallization characteristics of amorphous sugar (sucrose and alpha-lactose) preparations were analyzed, with the purpose of obtaining knowledge that could lead to the prediction of how long the amorphous state is retained under various conditions. The impact of compression, physical aging and freezing rate on the induction period (t(ind)) for crystallization were examined. Freeze-dried sugar samples were compressed at 74 or 443 MPa (5 min) and then rehumidified at specified RHs. Some freeze-dried sucrose samples were physically aged, and alternatively freeze-drying was conducted under different conditions. The isothermal crystallization of the prepared samples at different temperatures (T), the glass transition and the crystallization temperature (T-cry) were measured, using differential scanning calorimetry. The compression markedly decreased the t(ind), while significantly lowered the hygroscopicity. Physical aging and slower-freezing also shortened the t(ind). The t(ind) was found to be correlated exclusively with (T-cry-T), regardless of rehumidification, compression, sugar type, physical aging and freezing rate in the freeze-drying process. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jfoodeng.2012.05.004

Heterogeneity of the state and functionality of water molecules sorbed in an amorphous sugar matrix 査読

Koreyoshi Imamura, Ryo Kagotani, Mayo Nomura, Kohshi Kinugawa, Kazuhiro Nakanishi

CARBOHYDRATE RESEARCH 351 108 - 113 2012年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCI LTD

An amorphous matrix, comprised of sugar molecules, is frequently used in the pharmaceutical industry. An amorphous sugar matrix exhibits high hygroscopicity, and it has been established that the sorbed water lowers the glass transition temperature T-g of the amorphous sugar matrix. It is naturally expected that the random allocation and configuration of sugar molecules would result in heterogeneity of states for sorbed water. However, most analyses of the behavior of water, when sorbed to an amorphous sugar matrix, have implicitly assumed that all of the sorbed water molecules are in a single state. In this study, the states of water molecules sorbed in an amorphous sugar matrix were analyzed by Fourier-transform IR spectroscopy and a Fourier self-deconvolution technique. When sorbed water molecules were classified into five states, according to the extent to which they are restricted, three of the states resulted in a lowering of T-g of an amorphous sugar matrix, while the other two were independent of the plasticization of the matrix. This finding provides an explanation for the paradoxical fact that compression at several hundreds of MPa significantly decreases the equilibrium water content at a given RH, while the T-g remains unchanged. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2011.12.021

Rod-shaped Hydroxyapatite Nanoparticle Formation by Maturation with AOT 査読

Jun Oshitani, Nobuhide Kataoka, Mikio Yoshida, Kuniaki Gotoh, Koreyoshi Imamura

CHEMISTRY LETTERS 40 ( 10 ) 1085 - 1086 2011年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

Amorphous calcium phosphate nanoparticles were synthesized by mixing aqueous solutions of Ca(NO3)(2) and (NH4)(2)-HPO4. Then the particles were matured with sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) at various temperatures. Rod-shaped hydroxyapatite (HAp) nanoparticles were formed at maturation temperature >= 40 degrees C. These results indicate that addition of AOT nor during the particles synthesis but during the maturation at more equal critical temperature is a key to form the rod-shaped HAp nanoparticles using AOT.

DOI： 10.1246/cl.2011.1085

Cloning and expression of a β-galactosidase gene of Bacillus circulans. 査読

Song J, Imanaka H, Imamura K, Minoda M, Katase T, Hoshi Y, Yamaguchi S, Nakanishi K

Bioscience, biotechnology, and biochemistry 75 ( 6 ) 1194 - 1197 2011年6月

Rod-shaped Hydroxyapatite Nanoparticle Formation Using AOT and Water without Oil 査読

Jun Oshitani, Nobuhide Kataoka, Mikio Yoshida, Kuniaki Gotoh, Koreyoshi Imamura, Hidekazu Tanaka

CHEMISTRY LETTERS 40 ( 4 ) 400 - 401 2011年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

We synthesized rod-shaped hydroxyapatite (HAp) nanoparticles using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as an additive in water without an oil. The length of the particles increases from 40 to 100 nm with increasing the concentration ratio AOT/Ca while maintaining a width of 12 nm. These results indicate that an oil phase is not necessarily needed to form the rod-shaped HAp nanoparticles using AOT.

DOI： 10.1246/cl.2011.400

Influence of compression on water sorption, glass transition, and enthalpy relaxation behavior of freeze-dried amorphous sugar matrices 査読

Koreyoshi Imamura, Ryo Kagotani, Mayo Nomura, Kazuhiro Tanaka, Kohshi Kinugawa, Kazuhiro Nakanishi

INTERNATIONAL JOURNAL OF PHARMACEUTICS 408 ( 1-2 ) 76 - 83 2011年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

An amorphous matrix comprised of sugar molecules are frequently used in the pharmaceutical industry. The compression of the amorphous sugar matrix improves the handling. Herein, the influence of compression on the water sorption of an amorphous sugar matrix was investigated. Amorphous sugar samples were prepared by freeze-drying, using several types of sugars, and compressed at 0-443 MPa. The compressed amorphous sugar samples as well as uncompressed samples were rehumidified at given RHs, and the equilibrium water content and glass transition temperature (T-g) were then measured. Compression resulted in a decrease in the equilibrium water content of the matrix, the magnitude of which was more significant for smaller sized sugars. Diffusivity of water vapor in the sample was also decreased to one-hundredth by the compression. The T-g value for a given RH remained unchanged, irrespective of the compression. Accordingly, the decrease in T-g with increasing water content increased as the result of compression. The structural relaxation of the amorphous sugar matrices were also examined and found to be accelerated to the level of a non-porous amorphous sugar matrix as the result of the compression. The findings indicate that pores contained in freeze-dried sugar samples interfere with the propagation of structural relaxation. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ijpharm.2011.01.052

Causes of the production of multiple forms of β-galactosidase by Bacillus circulans. 査読

Song J, Abe K, Imanaka H, Imamura K, Minoda M, Yamaguchi S, Nakanishi K

Bioscience, biotechnology, and biochemistry 75 ( 2 ) 268 - 278 2011年2月

Multiple States of Sorbed Water Molecules in Amorphous Sugar Matrix andtheir Different Impacts on Physical Properties of the Matrix 査読

Koreyoshi Imamura

japan journal of food engineering 12 ( 1 ) 1 - 9 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）

Amorphous materials, comprised of sugar molecules, exhibit high hygroscopicity and the sorbed water exerts a major influence on physical stability of the matrix. To date, the water sorption behavior of amorphous sugars has been extensively investigated. However, most studies of the behavior of water, when sorbed to an amorphous sugar matrix, have implicitly assumed that all of the sorbed water molecules are in a single state: It is naturally expected that the random allocation and configuration of sugar molecules would result in heterogeneity of states for the sorbed water. Recently, we demonstrated the heterogeneity of state and functionality of water sorbed in amorphous sugar matrices by combining a Fourier transform IR spectroscopy and Fourier self-deconvolution technique
The sorbed water molecules were classified into five states, and the three of them mainly served to lower the glass transition temperature of an amorphous sugar matrix while the other two appeared to be independent of physical properties of the matrix. © 2011, Japan Society for Food Engineering. All rights reserved.

DOI： 10.11301/jsfe.12.1

Water Sorption, Glass Transition, and Protein-Stabilizing Behavior of an Amorphous Sucrose Matrix Combined With Various Materials 査読

Koreyoshi Imamura, Toru Yokoyama, Atsushi Fukushima, Mitsunori Kinuhata, Kazuhiro Nakanishi

JOURNAL OF PHARMACEUTICAL SCIENCES 99 ( 11 ) 4669 - 4677 2010年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JOHN WILEY & SONS INC

The effects of various additives on the physical properties of an amorphous sugar matrix were compared. Amorphous, sugar-additive mixtures were prepared by freeze-drying and then rehumidified at given RHs. Sucrose and eighteen types of substances were used as the sugar and the additive, respectively, and water sorption, glass-to-rubber transition, and protein stabilization during freeze-drying for the various sucrose-additive mixtures were examined. The additives were categorized into two groups according to their effects on T(g) and water sorption. Presence of polysaccharides, cyclodextrins, and polymers (large-sized additives) resulted in a decrease in equilibrium water content from the ideal value calculated from individual water contents for sucrose and additive, and in contrast, low MW substances containing ionizable groups (small-ionized additives) resulted in an increase. The increase in T(g) by the addition of large-sized additives was significant at the additive contents >50 wt.% whereas the T(g) was markedly increased in the lower additive content by the addition of small-ionized additives. The addition of small-ionized additives enhanced the decrease in T(g) with increasing water content. The protein stabilizing effect was decreased with increasing additive content in the cases of the both groups of the additives. (C) 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4669-4677, 2010

DOI： 10.1002/jps.22162

Development of a highly efficient indigo dyeing method using indican with an immobilized beta-glucosidase from Aspergillus niger 査読

Jingyuan Song, Hiroyuki Imanaka, Koreyoshi Imamura, Kouichi Kajitani, Kazuhiro Nakanishi

JOURNAL OF BIOSCIENCE AND BIOENGINEERING 110 ( 3 ) 281 - 287 2010年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SOC BIOSCIENCE BIOENGINEERING JAPAN

A highly efficient method for dyeing textiles with indigo is described. In this method, the substrate, indican is first hydrolyzed at an acidic pH of 3 using an immobilized beta-glucosidase to produce indoxyl, under which conditions indigo formation is substantially repressed. The textile sample is then dipped in the prepared indoxyl solution and the textile is finally exposed to ammonia vapor for a short time, resulting in rapid indigo dyeing. As an enzyme, we selected a beta-glucosidase from Aspergillus niger, which shows a high hydrolytic activity towards indican and was thermally stable at temperatures up to 50-60 degrees C, in an acidic pH region. The A. niger beta-glucosidase, when immobilized on Chitopearl BCW-3001 by treatment with glutaraldehyde, showed an optimum reaction pH similar to that of the free enzyme with a slightly higher thermal stability. The kinetics for the hydrolysis of indican at pH 3, using the purified free and immobilized enzymes was found to follow Michaelis-Menten type kinetics with weak competitive inhibition by glucose. Using the immobilized enzyme, we successfully carried out repeated-batch and continuous hydrolyses of indican at pH 3 when nitrogen gas was continuously supplied to the substrate solution. Various types of model textiles were dyed using the proposed method although the color yield varied, depending on the type of textile used. (C) 2010, The Society for Biotechnology, Japan. All rights reserved.

DOI： 10.1016/j.jbiosc.2010.03.010

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