研究者詳細 - 今村　維克

論文 - 今村　維克

分割表示 150 件中 141 - 150 件目／全件表示 >>

Isolation of a Novel Acylase from Streptomyces mobaraensis for Synthesis of Useful Amide Compounds

Zhang Demin, Koreishi Mayuko, Imamura Koreyoshi, Sakiyama Takaharu, NAKANISHI Kazuhiro

化学工学会研究発表講演要旨集 2003 136 - 136 2003年

Regulation of the Excretion of O-Acetyl-L-serine from Recombinant Escherichia coli Cells and Its Application to Synthesis of L-Cysteine and Non-protein Amino Acids

ZHAO Chunhui, OHNO Katsuhiro, SOGOH Kohji, IMAMURA Koreyoshi, SAKIYAMA Takaharu, NAKANISHI Kazuhiro

化学工学会研究発表講演要旨集 2003 685 - 685 2003年

Enzymatic synthesis of N-acyl-L-amino acids in a glycerol-water system using acylase I from pig kidney 査読

E Wada, M Handa, K Imamura, T Sakiyama, S Adachi, R Matsuno, K Nakanishi

JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY 79 ( 1 ) 41 - 46 2002年1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：AMER OIL CHEMISTS SOC A O C S PRESS

N-Medium- and long-chain acyl-L-amino acids were enzymatically synthesized from the corresponding L-amino acids and fatty acids using a reverse hydrolysis. Enzymes that are suitable for the synthetic reaction of N-acyl-L-amino acids were screened on the basis of hydrolytic activity toward N-lauroyl-L-glutamic acid as an indicator. Acylase I from pig kidney (EC 3.5.1.14) showed the highest N-acyl-L-amino acid hydrolytic activity among 57 commercially available enzymes tested. Acylase I effectively catalyzed the synthesis of N-lauroyl-L-amino acids except for N-lauroyl-L-proline and N-lauroyl-L-tyrosine in a glycerol-water system. Under the optimized reaction conditions, N-lauroyl-L-arginine and N-lauroyl-L-glutamic acid were obtained in conversions of 82 and 44%, respectively. The equilibrium constants calculated from the conversion obtained were 5.6, 15.4, 18.0, and 39.4 for the syntheses of N-lauroyl-L-glutamic acid, N.-lauroyl-L-lysine, N-lauroyl-L-glutamine, and N-lauroyl-L-methionine, respectively. N-Acyl-L-arginines with myristic acid and palmitic acid as the fatty acid were also synthesized using acylase I.

DOI： 10.1007/s11746-002-0432-7

Web of Science

J-GLOBAL

researchmap

Enzymatic modification of beta-lactoglobulin with N-fatty-acyl-dipeptide by transglutaminase from Streptomyces mobaraense 査読

E Wada, H Masuda, K Imamura, T Sakiyama, S Adachi, R Matsuno, K Nakanishi

BIOTECHNOLOGY LETTERS 23 ( 17 ) 1367 - 1372 2001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：SPRINGER

beta -Lactoglobulin was enzymatically acylated with N-lauroyl-L-glutaminyl-glycine and N-lauroyl-L-glutamyl-L-lysine using transglutaminase from Streptomyces mobaraense. The modification of the protein with N-fatty-acyl-dipeptide was confirmed by SDS-PAGE, gel chromatography, HPLC, amino acid analysis, and TOF-MS. The degrees of the protein modification with N-lauroyl-L-glutaminyl-glycine and N-lauroyl-L-glutamyl-L-lysine were estimated to be 2-4 and 1.5 residues per molecule, respectively.

DOI： 10.1023/A:1011699921628

Web of Science

researchmap

Role of sucrose-LDH hydrogen bond for thermal stabilizing effect of sucrose on freeze-dried LDH 査読

T Suzuki, K Imamura, H Fujimoto, M Okazaki

DRYING TECHNOLOGY 17 ( 7-8 ) 1429 - 1439 1999年

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

Relationship between thermal stabilizing effect of sugar on freeze-dried protein and sugar-protein hydrogen bond is studied. Sucrose and lactate dehydrogenase (LDH) are used as models for sugar and protein. Samples of freeze-dried LDH involved in sucrose of different crystallinity were prepared, and measurement of X-ray diffractometry (XRD) and Fourier-Transform Infrared (FT-IR) spectroscopy was done. It is found that when sucrose is amorphous, the degree of hydrogen bond formation is high and LDH is stabilized; when sucrose is crystalline, hydrogen bond is less formed and LDH is inactivated. These results indicate that the stabilizing effect of sugar is closely related to sugar-protein hydrogen bond. It is also found that there is an optimum sucrose content for the thermal stabilizing effect. This is because amorphous structure of sucrose is stabilized and protected from crystallization by LDH. Thus we can deduce that sugars and proteins work together to keep the activities of proteins.

DOI： 10.1080/07373939908917625

Web of Science

researchmap

Relation between thermal stabilizing effect of sucrose on LDH and sucrose-LDH hydrogen bond 査読

T Suzuki, K Imamura, H Fujimoto, M Okazaki

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 31 ( 4 ) 565 - 570 1998年8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 CHEMICAL ENG JAPAN

The thermal stabilizing effect of sugar on freeze-dried protein is studied, in particular on the relationship between the thermal stabilizing effect and the degree of sugar-protein hydrogen bond formation. Sucrose and lactate dehydrogenase (LDH) are used as models for sugar and protein. Several freeze-dried samples of LDH involved in sucrose were prepared; they differed in the degree of crystallinity of sucrose, By X-ray diffractometry (XRD) and Fourier transform infrared (FT-IR) spectroscopy, it is found that when sucrose is amorphous in the samples, the degree of hydrogen bond formation is high and LDH is stabilized remarkably. In contrast, when sucrose is crystalline, the degree of hydrogen bond formation is low and LDH is inactivated. These results indicate that the stabilizing effect of sugar is closely related to the sugar-protein hydrogen bond. The influence of sucrose content on the thermal stabilizing effect is also investigated. It is found that there is an optimum sucrose content for the thermal stabilizing effect. This is because, by the presence of LDH, the amorphous structure of sucrose is stabilized and protected from crystallization that causes loss of sucrose-LDH hydrogen bonds. Thus, we can deduce that sugars and proteins work together to maintain protein activities.

DOI： 10.1252/jcej.31.565

Web of Science

researchmap

Thermal stabilization of freeze-dried enzymes by sugars 査読

T Suzuki, K Imamura, K Yamamoto, T Satoh, M Okazaki

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 30 ( 4 ) 609 - 613 1997年8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 CHEMICAL ENG JAPAN

The thermal stabilization effect of sugars on freeze-dried proteins is studied, particularly the relation between stabilizing effect and the degree of sugar crystallinity. Three kinds of enzymes, alcohol dehydrogenase (ADH), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH), were used as model proteins. Aqueous solutions of enzymes with sugars were freeze-dried and stored in dry air at 65 degrees C. The stabilities of freeze-dried enzymes improve remarkably by addition of trehalose or raffinose. By measurement of X-ray diffractometry, the sugars are found to form fully amorphous matrix in freeze-dried samples. Furthermore, sucrose stabilizes enzymes to a great extent when it is amorphous in samples, though it shows Little stabilizing effect when it is crystalline. These results indicate that the stabilizing effect of sugars closely relates to the amorphous matrix formed by the sugars.

DOI： 10.1252/jcej.30.609

Web of Science

researchmap

Stabilizing effect on freeze-dried proteins by amorphous matrices of sugars 査読

T Suzuki, K Imamura, K Yamamoto, M Okazaki

DRYING '96, VOL B 1261 - 1266 1996年

A New Method for Measurement of Powder Characteristics Based on Reentrainment Phenomena 査読

Hiroaki Masuda, Shuji Matsusaka, Koreyoshi Imamura

KONA Powder and Particle Journal 12 133 - 143 1994年

記述言語：英語掲載種別：研究論文（学術雑誌）

A new method has been developed to measure and evaluate the operational powder characteristics for fine particle processing based on the reentrainment phenomena. Experiments on particle reentrainment were carried out using an accelerated air flow for 21 different test powders. Both the reentrainment fluxes, which were measured by an electrostatic method, and the average air velocities were automatically sampled by a computer. The sampled data were processed to obtain the reentrainment profiles as a function of the average air velocity. The cumulative reentrainment efficiencies were also obtained and represented as a function of the wall shear stress. It was found that fine particles having tendencies to form large aggregates were reentrained mainly in the early stage of the measurement when the flow velocity was as low as 5 m·s−1. Also, the mass ratio of the reentrained large aggregates to the total particles was used to obtain information on the particle-particle (cohesion) or particle-wall interactions (adhesion). On the other hand, the cumulative reentrainment efficiency-curves must be applied to determine the operational conditions controlling the amount of adhered particles in various aerosol processes. © 1994, Hosokawa Powder Technology Foundation. All rights reserved.

DOI： 10.14356/kona.1994021

Scopus

researchmap

飛散現象を利用した粉体特性の測定と評価

増田弘昭, 松坂修二, 今村維克

粉体工学会誌 29 ( 12 ) 897 - 905 1992年

記述言語：日本語出版者・発行元：The Society of Powder Technology, Japan

A new method has been developed to measure and evaluate the operational powder characteristics for fine particle processing based on the reentrainment phenomena. Experiments on particle reentrainment were carried out by use of an accelerated air flow for 21 different test powders. Both the reentrainment fluxes, which were measured by an electrostatic method, and the average air velocities were automatically sampled in a computer. The sampled data were processed to give the reentrainment profiles as a function of the average air velocity. The cumulative reentrainment efficiencies were also obtained and represented by a function of the wall shear stress.<br>It was found that fine particles having tendencies to form large aggregates were reentrained mainly in the early stage of the measurement where the flow velocity was as low as 5m·s^-1. Also, the mass ratio of the reentrained large aggregates to the total particles was well applied to obtain the information on the particle-particle or particle-wall interactions. On the other hand, the cumulative reentrainment efficiency-curves would be applied to determine the operational conditions controlling the amount of adhered particles in various aerosol processes.

DOI： 10.4164/sptj.29.897

CiNii Article

researchmap

　前のページ - 次のページ　

<今村 維克>

論文 - 今村 維克

<今村　維克>

論文 - 今村　維克