共查询到20条相似文献,搜索用时 31 毫秒
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《Bioorganic & medicinal chemistry》2014,22(2):684-691
Tocopherols (TOH) are lipophilic antioxidants which require the phenolic OH group for their redox activity. In contrast, non-redox active esters of α-TOH with succinate (α-TOS) were shown to possess proapoptotic activity in cancer cells. It was suggested that this activity is mediated via mitochondrial inhibition with subsequent production triggering apoptosis and that the modification of the linker between the succinate and the lipophilic chroman may modulate this activity. However, the specific mechanism and the influence of the linker are not clear yet on the level of the mitochondrial respiratory chain. Therefore, this study systematically compared the effects of α-TOH acetate (α-TOA), α-TOS and α-tocopheramine succinate (α-TNS) in cells and submitochondrial particles (SMP). The results showed that not all cancer cell lines are highly sensitive to α-TOS and α-TNS. In HeLa cells α-TNS did more effectively reduce cell viability than α-TOS. The complex I activity of SMP was little affected by α-TNS and α-TOS while the complex II activity was much more inhibited (IC50 = 42 ± 8 μM α-TOS, 106 ± 8 μM α-TNS, respectively) than by α-TOA (IC50 >1000 μM). Also the complex III activity was inhibited by α-TNS (IC50 = 137 ± 6 μM) and α-TOS (IC50 = 315 ± 23 μM). Oxygen consumption of NADH- or succinate-respiring SMP, involving the whole electron transfer machinery, was dose-dependently decreased by α-TOS and α-TNS, but only marginal effects were observed in the presence of α-TOA. In contrast to the similar inhibition pattern of α-TOS and α-TNS, only α-TOS triggered formation in succinate- and NADH-respiring SMP. Inhibitor studies excluded complex I as source and suggested an involvement of complex III in production. In cancer cells only α-TOS was reproducibly able to increase levels above the background level but neither α-TNS nor α-TOA. Furthermore, the stability of α-TNS in liver homogenates was significantly lower than that of α-TOS. In conclusion, this suggests that α-TNS although it has a structure similar to α-TOS is not acting via the same mechanism and that for α-TOS not only complex II but also complex III interactions are involved. 相似文献
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Yuanyuan Huang Renbang Zhao Yencon Hung Huiyu Gao Penghui Zhang Yang Wang Mengying Sun Dan Liu Shuai Wang 《Saudi Journal of Biological Sciences》2018,25(2):226-233
The degradation process of acephate in aqueous solution with OH and produced by 60Co-γ irradiation and electron pulse radiolysis was studied in the present paper. In the aqueous solution, acephate reacted with and transformed to transient species which can absorb weakly in the wavelength range of 300–400?nm and decay very fast. According to the decay of hydrated electron, the reaction rate constant of and acephate is (3.51?±?0.076)?×?109?dm3·mol?1·s?1. The transient species produced in the reaction of OH and acephate do not distinctly absorb the light in the wavelength range of 300–700?nm, so the decay and kinetics of the transient species cannot determinedirectly. The competing reaction of KSCN oracephate with OH were studied to obtain the reaction rate constant of OH and acephate, which is (9.1?±?0.11)?×?108?dm3·mol?1·s?1. Although acetylamide and inorganic ions were determined in the products of the reaction of acephate with OH or , the concentration of inorganic ions in the products of the reaction of acephate with OH is higher than that in the product of the reaction of acephate with . Moreover, there were sulfide in the products of the reaction of acephatewith . The degradation pathways of acephate by OH and were also proposed based on the products from GC-MS. 相似文献
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《Bio Systems》2009,95(3):233-241
A computer study of the prediction of the protein crystal’s shape and polymorphism of crystal’s structures within the limits resulting from the exploration of the Miyazawa–Jernigan matrix is presented. In this study, a coarse-graining procedure was applied to prepare a two-dimensional growth unit, where instead of full atom representation of the protein a two-type (hydrophobic–hydrophilic, HP) aminoacidal representation was used. The interaction energies between hydrophobic () aminoacids were chosen from the well-known HP-type models (), whereas interaction energies between hydrophobic and hydrophilic aminoacids () as well as interaction energies between hydrophilic aminoacids () were chosen from the range: , but not all values from this range fulfiled limitations resulting from the exploration of the Miyazawa–Jernigan matrix. Exploring every positively vetted combinations of energy interactions a polymorphism of the unit cell was observed what led to the fact that different final crystal’s shapes were obtained. 相似文献
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