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21.
Abstract The Gibbs ensemble Monte Carlo simulation has been used to calculate vapour-liquid equilibria of a Lennard-Jones (LJ) binary mixture. The mixture studied is the LB-2-1 model which has been used in our previous calculations on PVT relation and density-dependent local composition. The P-x-y relation has been established at two different temperatures and used to determine vapour-liquid coexistence region in the PVTx space. 相似文献
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Yousuke Kouno Makoto Anraku Keishi Yamasaki Yoshiro Okayama Daisuke Iohara Yu Ishima Toru Maruyama Ulrich Kragh-Hansen Fumitoshi Hirayama Masaki Otagiri 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Sodium octanoate (Oct) and N-acetyl-l-tryptophan (N-AcTrp) are widely used as stabilizers during pasteurization and storage of albumin products. However, exposure to light photo-degrades N-AcTrp with the formation of potentially toxic compounds. Therefore, we have examined the usefulness of N-acetyl-l-methionine (N-AcMet) in comparison with N-AcTrp for long-term stability, including photo stability, of albumin products.Methods
Recombinant human serum albumin (rHSA) with and without additives was photo-irradiated for 4 weeks. The capability of the different stabilizers to scavenge reactive oxygen species (ROS) was examined by ESR spectrometry. Carbonyl contents were assessed by a spectrophotometric method using fluoresceinamine and Western blotting, whereas the structure of rHSA was examined by SDS-PAGE, far-UV circular dichroism and differential scanning calorimetry. Binding was determined by ultrafiltration.Results
N-AcMet was found to be a superior ROS scavenger both before and after photo-irradiation. The number of carbonyl groups formed was lowest in the presence of N-AcMet. According to SDS-PAGE, N-AcMet stabilizes the monomeric form of rHSA, whereas N-AcTrp induces degradation of rHSA during photo-irradiation. The decrease in α-helical content of rHSA was the smallest in the presence of Oct, without or with N-AcMet. Photo-irradiation did not affect the denaturation temperature or calorimetric enthalpy of rHSA, when N-AcMet was present.Conclusion
The weakly bound N-AcMet is a superior protectant of albumin, because it is a better ROS-protector and structural stabilizer than N-AcTrp, and it is probable and also useful for other protein preparations.General significance
N-AcMet is an effective stabilizer of albumin during photo-irradiation, while N-Ac-Trp promotes photo-oxidative damage to albumin. 相似文献25.
Oda A Wada I Miura K Okawa K Kadoya T Kato T Nishihara H Maeda M Tanaka S Nagashima K Nishitani C Matsuno K Ishino M Machesky LM Fujita H Randazzo P 《The Journal of biological chemistry》2003,278(8):6456-6460
Searching for proteins in platelets that can interact with the N-terminal SH3 domain of CrkL (using a combination of a pull-down assay followed by mass spectrometry), we have found that human platelets express an ADP-ribosylation factor (Arf)-specific GTPase-activating protein (GAP), ASAP1, as a CrkL-binding protein. In spreading platelets, most endogenous ASAP1 is localized at peripheral focal adhesions. To determine the physiologic significance of the CrkL-ASAP1 association, we overexpressed CrkL, ASAP1, or both in combination in COS7 cells. Unlike endogenous ASAP1 in platelets, overexpressed ASAP1 showed diffuse cytoplasmic distribution. However, when co-expressed with wild-type CrkL, both endogenous and expressed ASAP1 accumulated at CrkL-induced focal adhesions. An SH2-mutated CrkL, which cannot localize at focal adhesions, failed to recruit ASAP1 into focal adhesions. Thus, CrkL appears to be a lynchpin between ASAP1 and peripheral focal adhesions. 相似文献
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Changes in the motility time of spermatozoa collected from the testes and the sperm duct of normal and sex-reversed male (XX) rainbow trout in physiological balanced salt solution were examined after incubation in artificial seminal plasmas of various pHs. Although untreated spermatozoa from the sperm duct retained motility for 60–90 s in the balanced salt solution, the spermatozoa collected from the testes were immotile. During the incubation in artificial seminal plasma of pH 7.0, the spermatozoa from the sperm duct hardly moved, similar to the testicular spermatozoa in the balanced salt solution. By suspending and incubating the testicular spermatozoa in artificial seminal plasma of pH 9.9 for 2 h at 4°C, the percentage of motile spermatozoa increased from 0–5% to 80%. The spermatozoa remained motile for at least 2 min after long-term incubation (12 h). When the full-sib eggs were inseminated with untreated testicular spermatozoa or testicular sperm treated for 2 h at high pH, the percentage survival increased from 5.5% to 53.8% at the eyed stage due to the high-pH treatment. The incubation of the spermatozoa in high-pH artificial seminal plasma improved the motility of the spermatozoa from the testes of the sex-reversed male that had lost its sperm duct. By this treatment, it is possible to markedly increase the mass production efficiency of all-female or all-female triploid sterile progenies. 相似文献
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Toru Nakayama Nobuyoshi Esaki Woon-Joo Lee Izumi Tanaka Hidehiko Tanaka Kenji Soda 《Bioscience, biotechnology, and biochemistry》2013,77(9):2367-2369
Four types of β-xylosidases from a concentrated culture filtrate of Pénicillium wortmanni IFO 7237, designated as xylosidase-1, -2, -3, and -4 were purified to homogeneity on SDS polyacrylamide gel electrophoresis by an alcohol precipitation, DEAE-Sephadex A-25 ion exchange chromatography, and isoelectric focusing. The molecular weights of xylosidase-1, -2, -3, and -4 were estimated to be 110,000, 195,000, 210,000, and 180,000 respectively and their isoelectric points to be 3.7, 4.28, 4.6, and 4.8. The pH optima of β-xylosidase activities were from 3 to 4.5. The optimum temperature for enzyme activities was from 55°C to 65°C. On the enzymic hydrolysis of phenyl ß-d- xyloside, the reaction product of each enzyme was found to be β-d-xylose with retention of configuration. All the four ß-xylosidases were free of α-xylosidase and ß-glucosidase activities. All the enzyme activities of four β-xylosidases were strongly inhibited by Hg2+ and N- bromosuccinimide. With respect to the hydrolysis patterns and HPLC analysis of hydrolyzates from xylooligosaccharides, xylosidase-2 was totally different from other three as a distinct enzyme. Xylosidase-1 was also in a separate group although xylosidase-3 and -4 showed closely related action patterns as a different group. 相似文献
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Biodegradation of five chemicals (aniline, anthracene, chlornitrophen (CNP), fenitrothion (FNT) and linear alkylbenzene sulphonate (LAS)) by aquatic bacteria in three different types of ponds was determined according to the cultivation method developed by this group. The degradability toward these chemicals was varied among the ponds, except for LAS which was decomposed well in all samples. Higher degradability towards the two agrochemicals, CNT and FNT, was found in the pond surrounded by paddy fields, whereas aniline and anthracene were decomposed more rapidly in the pond located in the industrial area. Water from the pond in the botanical garden, with the least exposure to any chemicals, exhibited the lowest degradation toward all chemicals tested. There was no significant seasonal variation in the biodegradation of chemicals in these ponds. It was deduced that biodegradability toward certain chemicals could be a result of acclimatization of the microbial community by chemical contamination present and past, suggesting the possible use of biodegradation profiles as an indicator for chemical pollution in the aquatic environment. 相似文献
30.
The dissociation constant (Kd) for CO from neuronal nitric oxide synthase heme in the absence of the substrate and cofactor was less than 10−3 μM. In the presence of
-Arg, it dramatically increased up to 1 μM. In the presence of inhibitors such as NG-nitro-
-arginine methyl ester and 7-nitroindazole (NI), the Kd value further increased up to more than 100 μM. Addition of the cofactor, 5,6,7,8-tetrahydrobiopterin (H4B), increased the Kd value by 10-fold in the presence of
-Arg, whereas it decreased the value to less than one 250th in the presence of NI. Addition of H4B increased the recombination rate constant (kon) for CO by more than two-fold in the presence of
-Arg or N6-(1-iminoethyl)-
-lysine, whereas it decreased the kon value by three-fold in the presence of
-thiocitrulline. Thus, the binding fashion of some of inhibitors, such as NI, may be different from that of
-Arg with respect to the H4B effect. 相似文献
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