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101.
The effects of a nonionic surfactant, polyoxyethylene mono-N-dodecyl-ether (Brij 35; number of units of ethylene oxide moieties, 23), on the behavior of Bacillus amyloliquefaciens α-amylase in the hydrolysis of maltoheptaose were studied at 25°C and pH 7.0. The addition of the surfactant to the enzyme-substrate
system increased the amount of reducing sugars during the hydrolysis. A high-performance liquid chromatography technique was
used for the determination of the hydrolysis products. During the hydrolysis, the concentration of maltose was increased by
the addition of the surfactant, whereas the concentrations of other products were unchanged. Therefore, the increase in the
amount of reducing sugars was thought to be due to the increase of the maltose fragment. Because the transglycosylation of
hydrolyzed maltose takes place during the hydrolysis, the suppression of transglycosylation accelerates the production of
total reducing sugars. The interaction between the maltose fragment and micelle surface might induce the release of this fragment
from the enzyme active site and then suppress the transglycosylation. The bindings of the enzyme, the substrate, and/or the
products to the micelle surface may affect the hydrolytic behavior including both the hydrolysis and transglycosylation catalytic
conversions. 相似文献
102.
Yasutaka Morita Kenji Kondoh Quamrul Hasan Toshifumi Sakaguchi Yuji Murakami Kenji Yokoyama Eiichi Tamiya 《Journal of the American Oil Chemists' Society》1997,74(11):1377-1383
Protease activity was detected in the culture medium of Serratia marcescens AP3801 grown at 10°C, which was isolated from soil collected from the top of a mountain. The enzyme, designated as CP-58
protease, was purified to homogeneity from the culture broth by ion exchange and gel filtration chromatographies. The molecular
mass of the protease was 58 kDa, and its isoelectric point was close to 6.0. Maximal activity toward azocasein was observed
at 40°C and from pH 6.5 to 8.0. The activity was strongly inhibited by 1,10-phenanthroline, suggesting that the enzyme is
a metalloprotease. The N-terminal amino acid sequence was Ser-Leu-Asn-Gly-Lys-Thr-Asn-Gly-Trp-Asp-Ser-Val-Asn-Asp-Leu-Leu-Asn-Tyr-His-Asn-Arg-Gly-Asn
(or Asp)-Gly-Thr-Ile-Asn-Asn-Lys-Pro-Ser-Phe-Asp-Ile-Ala. A search through databases for sequence homology aligned CP-58 protease
with metalloprotease. The result of the cleavage pattern of oxidized insulin B-chain suggests that CP-58 protease has a broader
specificity than other proteases against the peptide substrate. 相似文献
103.
Yusuke Yoshiyasu Wan‐Chun Ma Eiichi Yoshida Fumio Kanehiro 《Computer Graphics Forum》2014,33(5):257-267
We present a non‐rigid surface registration technique that can align surfaces with sizes and shapes that are different from each other, while avoiding mesh distortions during deformation. The registration is constrained locally as conformal as possible such that the angles of triangle meshes are preserved, yet local scales are allowed to change. Based on our conformal registration technique, we devise an automatic registration and interactive registration technique, which can reduce user interventions during template fitting. We demonstrate the versatility of our technique on a wide range of surfaces. 相似文献
104.
Imoto Taiji; Yamada Hidenori; Yasukochi Takanori; Yamada Eiichi; Ito Yuji; Ueda Tadashi; Nagatani Hiroko; Miki Takeyoshi; Horiuchi Tadao 《Protein engineering, design & selection : PEDS》1987,1(4):333-338
In the preceding paper in this issue, we described the overproduction of one mutant chicken lysozyme in Escherichia coil.Since this lysozyme contained two amino acid substitutions (Ala31ValandAsn106Ser)in addition to an extra methionine residue at theNH2-terminus the substituted amino acid residues were convertedback to the original ones by means of oligonucleotide-directedsite-specific mutagenesis and in vitro recombination. Thus fourkinds of chicken lysozyme [Met1 Val31Ser106-, Met1Ser106-,Met1 Val31-and Met1 (wild type)] wereexpressed in E. coli. From the results of folding experimentsof the reduced lysozymes by sulfhydryl-disulfide interchangeat pH 8.0 and 38°C, follow ed by the specific activity measurementsof the folded en zymes, the following conclusions can be drawn:(i) an extra methionine residue at the NH2-terminus reducesthe folding rate but does not affect the lysozyme activity ofthe folded enzyme; (ii) the substitution of Asn106 by Ser decreasesthe activity to 58% of that of intact native lysozyme withoutchanging the folding rate; and (iii) the substitution of Ala31Val prohibits the correct folding of lysozyme. Since the wildtype enzyme (Met1-lysozyme) was activated in vitro withoutloss of specific activity, the systems described in this study(mutagenesis, overproduction, purification and folding of inactivemutant lysozymes) may be useful in the study of folding pathways,expression of biological activity and stability of lysozyme. 相似文献
105.
Machiko Shimada Yoshio Nakamura Yasuo Kusama Osamu Matsuda Naoyuki Tamura Eiichi Kageyama 《应用聚合物科学杂志》1974,18(11):3387-3396
The types of free radicals produced in the water-accessible regions of cellulose I and cellulose II fibers by γ-irradiation in nitrogen atmosphere at room temperature were studied by ESR spectroscopy. The ESR spectra of the irradiated cellulose I and II change by contacting the fibers with water, and after immersion in water the spectral shape depends on the orientation of the fiber axes to the magnetic field. These spectra are probably related to the free radicals generated in the highly ordered regions inaccessible to water in irradiated cellulosic fibers. The ESR spectrum of free radicals generated in decrystallized cellulose after irradiation consists of a singlet and a doublet. When the ESR spectra of free radicals formed in the highly ordered regions of cellulose I and II and the singlet and the doublet are combined in adequate ratio, the constructed spectra are similar to those of the radicals scavenged by water in the irradiated cellulose I and II fibers. From these facts, the spectra due to the free radicals in the water-accessible regions in irradiated cellulose I and II are considered to consist of the singlet and the doublet formed by free radicals in the typical amorphous regions and the spectra of other types of radicals generated in the semicrystalline regions. 相似文献
106.
Eiichi Jinen 《Journal of Materials Science》1987,22(6):1956-1962
The effect of low-cycle fatigue on the creep properties of a fibre-reinforced thermoplastic has been examined from the standpoint of the stress dependence and cycle ratio, which is the fraction of the mean life cycles to fracture. The time dependence of the strain and the strain rate of a virgin specimen can be described by a straight line on a logarithmic scale, therefore the deformation process seems to be ruled by a flow law. In addition the time dependence of the strain rate does not indicate the stress dependence for each stress level, which shows the same value as in the gradient of these relations. In the case of fatigued specimens, however, a knee point which divides the creep process into a primary region and a secondary one appears in the creep relation. The gradient in the primary region is less than that for the virgin material, and the magnitude and the timing of its appearance show either a stress dependence or a cycle ratio dependence. A weak stress dependence of the relation for log against logt can also be found; however, the results do not indicate a dependence on the cycle ratio. The reason for these results and the relationship of the structural changes of the materials are discussed using a McLean model. 相似文献
107.
Abstract A system utilizing a microcomputer, electronic scalers, sensitive cup anemometers and a specially designed interface was used to measure wind speed profiles above a loblolly pine plantation. The design, operation and results using this system are described. 相似文献
108.
109.
Ken Yukimura Kenichi Ego Koichi Takaki Tamiya Fujiwara 《Surface & coatings technology》2007,201(15):6520-6522
A hybrid plasma is generated by combining a burst methane rf (195 kHz) plasma with a carbon shunting arc discharge. The shunting arc discharge triggers the rf methane plasma. As a result, the rf plasma is initiated over a wide range of ambient gas pressure from 0.045 Pa as a base pressure to a methane pressure of 1.26 Pa, at which the rf plasma is not self-ignited. When a target is immersed in the rf- and shunting arc-hybrid plasma, and a negative pulse voltage is applied to the target, carbon ions are extracted from the hybrid plasma. When the carbon shunting arc ionizes the methane gas, an rf plasma is initiated and the ionization of methane is significantly enhanced in the rf plasma. The plasma density in the hybrid plasma increases by a factor of approximately 5-9 compared to that of the shunting arc discharge. 相似文献
110.
Satoshi Takata Shunkichi Ueno Yasuhiro Tanabe Takashi Akatsu Eiichi Yasuda Yoshiharu Waku 《Ceramics International》2007,33(8):1569-1571
The internal friction behavior of a unidirectionally solidified Al2O3/YAG eutectic was examined between room temperature and 1400 °C. No internal friction was observed up to 1200 °C. Above 1200 °C, the internal friction drastically increased with increasing temperature and the number of torsional loading cycles. For the 1400 °C test, the internal friction gradually increased with the number of loading cycles and then saturated after 103 cycles. 相似文献