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1.
Luciferin‐Regenerating Enzyme Mediates Firefly Luciferase Activation Through Direct Effects of D‐Cysteine on Luciferase Structure and Activity 下载免费PDF全文
Roohullah Hemmati Saman Hosseinkhani Reza H. Sajedi Taha Azad Amin Tashakor Nuredin Bakhtiari Farangis Ataei 《Photochemistry and photobiology》2015,91(4):828-836
Luciferin‐regenerating enzyme (LRE) contributes to in vitro recycling of D‐luciferin. In this study, reinvestigation of the luciferase‐based LRE assay is reported. Here, using quick change site‐directed mutagenesis seven T‐LRE (Lampyris turkestanicusLRE) mutants were constructed and the most functional mutant of T‐LRE (T69R) was selected for this research and the effects of D‐ and L‐cysteine on T69R T‐LRE‐luciferase‐coupled assay are examined. Our results demonstrate that bioluminescent signal of T69R T‐LRE‐luciferase‐coupled assay increases and then reach equilibrium state in the presence of 5 mm D‐cysteine. In addition, results reveal that 5 mm D‐ and L‐cysteine in the absence of T69R T‐LRE cause a significant increase in bioluminescence intensity of luciferase over a long time as well as decrease in decay rate. Based on activity measurements, far‐UV CD analysis, ANS fluorescence and DLS (Dynamic light scattering) results, D‐cysteine increases the activity of luciferase due to weak redox potential, antiaggregatory effects, induction of changes in conformational structure and kinetics properties. In conclusion, in spite of previous reports on the effect of LRE on luciferase bioluminescent intensity, the majority of increase in luciferase light output and time‐course originate from the direct effects of D‐cysteine on structure and activity of firefly luciferase. 相似文献
2.
Mhaidat I. Taha Z. A. Al Momani W. Hijazi A. K. 《Russian Journal of General Chemistry》2019,89(12):2584-2590
Russian Journal of General Chemistry - Photoconductive acenaphthenequinone derivatives have been synthesized by a one-pot process of acenaphthenequinone with different aromatic hydrazides... 相似文献
3.
Waqas Jamil Sorath Solangi Muhammad Ali Khalid Muhammad Khan Muhammad Taha Muhammad Yar Khuhawar 《Arabian Journal of Chemistry》2019,12(8):2262-2269
2-Hydroxy salicylhydrazide isatin hydrazone (L) and its Mn (II), Co (II), Ni (II), Cu (II), and Zn (II), metal complexes were synthesized. 1H NMR, UV–Vis, IR spectroscopy and elemental (CHN/S) analysis techniques were applied for characterization. TG/DTA techniques revealed that all the synthetic compounds are thermally stable up to 300 °C. They were found non-electrolytes in nature. Furthermore, all these complexes were evaluated for antiglycation and DPPH radical scavenging activities. They showed varying degree of activity with IC50 values between 168.23 and 269.0 μM in antiglycation and 29.63–57.71 μM in DPPH radical scavenging activity. Mn (II), Co (II), Ni (II), Cu (II), and Zn (II), metal complexes showed good antiglycation as well as DPPH radical scavenging activity. The IC50 values for antiglycation activity are 168.23 ± 2.37, 234.27 ± 4.33, 257.1 ± 6.43, 267.7 ± 8.43, 269.0 ± 8.56 Ni for Co, Zn, Mn, Cu, and Ni complexes, respectively, while IC50 value were found to be 29.63 ± 2.76, 31.13 ± 1.41, 35.16 ± 2.45, 43.53 ± 3.12, 57.71 ± 2.61 μM for Cu, Zn, Mn, Co and Ni complexes, respectively, for DPPH radical scavenging activity. These synthesized metal complexes were found to be better active than standards Rutin (IC50 = 294.46 μM) for anti-glycation, and tert-butyl-4-hydroxyanisole (IC50 = 44.7 μM) for DPPH radical scavenging activity. 相似文献
4.
New ONS hydrazone ligand, 2-[(2-aminochromon-3-yl)methylidene]-N-phenylhydrazinecarbothioamide, HL , was synthesized and reacted with different salts of Cu (II) ion (OAc−, NO3−, SO42− and Cl−) in absence and presence of secondary ligands (L′); 8-hydroxyquinoline, 1,10-phenanthroline or SCN−; to form binary and ternary Cu(II)-chelates. The ligand and its Cu(II)-complexes were fully characterized by analytical, spectral, thermal, conductivity and magnetic susceptibility measurements. The metal chelates showed octahedral, square planar and /or distorted tetraherdal arrangements. Coats–Redfern equations used to calculate the kinetic parameters of the thermal decomposition stages (Ea, A, ΔH, ΔS and ΔG). The compounds exhibit luminescence property; promising interesting potential applications as photoactive materials. Lippert–Mataga, Bakhshiev, Kawski–Chamma–Viallet and microscopic solvent polarity parameter and ETN correlation methods were applied on the solvatochromic shifts of emission spectra to evaluate the ground (μg) and excited (μe) states dipole moments. Excited state dipole moment is larger than the ground state which may be attributed to π-π* transition. The coordinating anions play an important role on the position and intensity of emission band. The ligand and its metal complexes showed antimicrobial activity towards Gram–positive bacteria, Gram–negative bacteria, yeast and fungus. The molecular structural parameters of HL and its Cu(II)- complexes have been calculated on the basis of DFT engaged in the Gaussian 09 program at the B3LYP/6-31G(d,p) level; the theoretical data are correlated with the experimental data. 相似文献
5.
The degradation of the nearby generation of high‐density polyethylene (HDPE) loaded with 2.5% of carbon black (CB) content (ie, HDPE/CB composites) is studied experimentally with the end goal of radiation safety applications. The impact of various γ‐irradiation doses in the air on the nanostructure of free volume and durability has been researched. The free volume was evaluated utilizing the positron annihilation lifetime (PAL) technique while the durability was contemplated by measuring the mechanical properties such as strain, elongation at break, and tear resistance. The electrical conductivity was explored to demonstrate the impact of the irradiation dose on the conductivity of the samples. Surface morphology studies using a scanning electron microscope (SEM) showed the surface fracture of HDPE/CB composites for unirradiated and irradiated samples. The surface roughness of the HDPE/CB GMs increases with increasing the irradiation dose. Among various uses of HDPE/CB composites, sheets are liners of dumps used to dispose of interim storage for Low and Medium Level Waste of NORMs and TENORMs. HDPE Geomembrane liners proved its utilization from the results of present research of electrical, mechanical tests, and SEM morphology to have the required resistance to weather conditions. 相似文献
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7.
D. M. Al-Mailem M. K. Kansour S. S. Radwan 《Applied biochemistry and biotechnology》2014,174(5):1736-1751
Biofilm samples were established on glass slides by submerging them in oil-free and oil-containing sewage effluent for a month. In batch cultures, such biofilms were effective in removing crude oil, pure n-hexadecane, and pure phenanthrene contaminating sewage effluent. The amounts of the removed hydrocarbons increased with increasing biofilm surface area exposed to the effluent. On the other hand, addition of the reducing agent thioglycollate dramatically inhibited the hydrocarbon bioremediation potential of the biofilms. The same biofilm samples removed contaminating hydrocarbons effectively in three successive batch bioremediation cycles but started to become less effective in the cycles thereafter, apparently due to mechanical biofilm loss during successive transfers. As major hydrocarbonoclastic bacteria, the biofilms harbored species belonging to the genera Pseudomonas, Microvirga, Zavarzinia, Mycobacterium, Microbacterium, Stenotrophomonas, Gordonia, Bosea, Sphingobium, Brachybacterium, and others. The nitrogen fixer Azospirillum brasilense and the microalga Ochromonas distigma were also present; they seemed to enrich the biofilms, with nitrogenous compounds and molecular oxygen, respectively, which are known to enhance microbiological hydrocarbon degradation. It was concluded that man-made biofilms based upon sewage microflora are promising tools for bioremediation of hydrocarbons contaminating sewage effluent. 相似文献
8.
Taha M. A. Eldebss Ahmad M. Farag Adel Y. M. Shamy 《Journal of heterocyclic chemistry》2019,56(2):371-390
A series of new substituted benzimidazoles embedded with a variety of function groups has been synthesized from N‐methyl‐2‐bromoacetylbenzimidazole. The synthesized compounds were fully characterized, and their structures were elucidated based on elemental analysis, spectral data, and alternative synthetic pathways, whenever possible. Some of benzimidazole derivatives were tested as corrosion inhibitors. 相似文献
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