共查询到20条相似文献,搜索用时 78 毫秒
1.
Roichi?Itoh Christelle?Saint-Marc Stéphane?Chaignepain Riko?Katahira Jean-Marie?Schmitter Bertrand?Daignan-Fornier
Background
The purine salvage enzyme inosine 5'-monophosphate (IMP)-specific 5'-nucleotidase catalyzes degradation of IMP to inosine. Although this enzymatic activity has been purified and characterized in Saccharomyces cerevisiae, the gene encoding IMP 5'-nucleotidase had not been identified. 相似文献2.
Background
Microbial degradation of azo dyes is commonly initiated by the reduction of the azo bond(s) by a group of NADH or NADPH dependant azoreductases with many requiring flavin as a cofactor. In this study, we report the identification of a novel flavin-free NADPH preferred azoreductase encoded by azoB in Pigmentiphaga kullae K24. 相似文献3.
Xuelu Ding Vannuruswamy Garikapati Bernhard Spengler Sven Heiles 《Rapid communications in mass spectrometry : RCM》2018,32(16):1439-1450
Rationale
Neurosteroids are important signalling molecules that modulate neuronal activity. Their low concentrations and low volatility make neurosteroid detection and quantification by ambient mass spectrometry challenging. Here we develop a reactive low‐temperature plasma mass spectrometry (LTP‐MS) method and demonstrate its potential for fast screening and quantification of neurosteroids in mouse brain.Methods
Ketone‐based neurosteroids were analysed with the LTP‐MS method. The plasma of the LTP was heated in order to improve the desorption efficiency of low‐volatility neurosteroids. Methylamine with a concentration of 500 ppbv was employed as the reactive reagent. Neurosteroids in mouse brain tissue extracts were detected in 70 s with mass errors less than ±3 ppm due to coupling of the ion source with a high‐performance mass spectrometer.Results
Reaction between neurosteroids and methylamine, seeded into the LTP gas stream, resulted in the formation of protonated methylamine–neurosteroid adducts with 5‐ to 100‐fold abundances, compared to [M + H]+ ions detected in non‐reactive LTP‐MS. The lowest detectable concentrations of neurosteroid standards were in the range of ng/mL. Concentrations of neurosteroids in male and female mouse brain extracts as determined with reactive LTP‐MS were on the level of ng/g, comparable to results obtained with high‐performance liquid chromatography–tandem mass spectrometry.Conclusions
The developed reactive LTP‐MS is capable of providing sensitive identification and quantification of ketone‐based neurosteroids in mouse brain extracts with minimal sample treatment, and showcases the potential of reactive LTP‐MS as a tool for fast screening of neurosteroid levels in brain.4.
Tabatabaee M 《Chemistry Central journal》2012,6(1):5
Background
Various water clusters including hexamers, heptamers, octamers, decamers and 1D or 2D infinite water chains in a number of organic and inorganic-organic hybrid hosts, have been reported. 相似文献5.
Zhou Yu Sean E Reichheld Leslie Cuthbertson Justin R Nodwell Alan R Davidson 《BMC biochemistry》2010,11(1):34
Background
Increasing our understanding of antibiotic resistance mechanisms is critical. To enable progress in this area, methods to rapidly identify and characterize antibiotic resistance conferring enzymes are required. 相似文献6.
Thomas Pohl Julia Walter Stefan Stolpe Joel H Defeu Soufo Peter L Grauman Thorsten Friedrich 《BMC biochemistry》2007,8(1):13
Background
Frataxin is discussed as involved in the biogenesis of iron-sulfur clusters. Recently it was discovered that a frataxin homologue is a structural component of the respiratory NADH:ubiquinone oxidoreductase (complex I) in Thermus thermophilus. It was not clear whether frataxin is in general a component of complex I from bacteria. The Escherichia coli homologue of frataxin is coined CyaY. 相似文献7.
Rosa A Vacca Sergio Giannattasio Guido Capitani Ersilia Marra Philipp Christen 《BMC biochemistry》2008,9(1):17
Background
The pyridoxal-5'-phosphate (PLP)-dependent or vitamin B6-dependent enzymes that catalyze manifold reactions in the metabolism of amino acids belong to no fewer than four evolutionarily independent protein families. The multiple evolutionary origin and the essential mechanistic role of PLP in these enzymes argue for the cofactor having arrived on the evolutionary scene before the emergence of the respective apoenzymes and having played a dominant role in the molecular evolution of the B6 enzyme families. Here we report on an attempt to re-enact the emergence of a PLP-dependent protoenzyme. The starting protein was pancreatic ribonuclease A (RNase), in which active-site Lys41 or Lys7 readily form a covalent adduct with PLP. 相似文献8.
Sandra del Moral Clarita Olvera Maria Elena Rodriguez Agustin Lopez Munguia 《BMC biochemistry》2008,9(1):6
Background
Inulosucrase (IslA) from Leuconostoc citreum CW28 belongs to a new subfamily of multidomain fructosyltransferases (FTFs), containing additional domains from glucosyltransferases. It is not known what the function of the additional domains in this subfamily is. 相似文献9.
Background
The alkaline protease from Pseudomonas aeruginosa(AprA) is a member of the metzincin superfamily of metalloendoproteases. A key feature of these proteases is a conserved methionine-containing 1,4-tight β turn at the base of the active site zinc binding region. 相似文献10.
Background
We have recently identified a new thiamine derivative, adenosine thiamine triphosphate (AThTP), in E. coli. In intact bacteria, this nucleotide is synthesized only in the absence of a metabolizable carbon source and quickly disappears as soon as the cells receive a carbon source such as glucose. Thus, we hypothesized that AThTP may be a signal produced in response to carbon starvation. 相似文献11.
Shu-Chuan Lin Wei-Ting Liu Shi-Hwei Liu Wei-I Chou Bor-Kai Hsiung I-Ping Lin Chia-Chin Sheu Margaret Dah-Tsyr Chang 《BMC biochemistry》2007,8(1):9
Background
Rhizopus oryzaeglucoamylase (RoGA) consists of three domains: an amino (N)-terminal raw starch-binding domain (SBD), a glycosylated linker domain, and a carboxy (C)-terminal catalytic domain. The 36-amino-acid linker region (residues 132–167) connects the two functional domains, but its structural and functional roles are unclear. 相似文献12.
Niklas?Darin Norman?Kadhom Jean-Jacques?Brière Dominique?Chretien Cécile?M?Bébéar Agnès?R?tig Arnold?Munnich Pierre?Rustin
Background
Mycoplasma contaminations are a recurrent problem in the use of cultured cells, including human cells, especially as it has been shown to impede cell cycle, triggering cell death under various conditions. More specific consequences on cell metabolism are poorly known. 相似文献13.
Alex S Powlesland Maria Marcela Barrio José Mordoh Paul G Hitchen Anne Dell Kurt Drickamer Maureen E Taylor 《BMC biochemistry》2011,12(1):13
Background
The Lewisx trisaccharide, also referred to as the CD15 antigen, is a diagnostic marker used to distinguish Hodgkin's lymphoma from other lymphocytic cancers. However, the role of such fucosylated structures remains poorly understood, in part because carriers of Lewisx structures on Hodgkin's Reed-Sternberg cells have not been identified. 相似文献14.
Thekku Veedu Sreevidya Gilad Golden Noam Saper Jared Feldman Mark Botoshansky Menahem Kaftory 《Structural chemistry》2011,22(5):1105-1112
Abstract
The preparation and crystal structure of six molecular compounds consist of light-stable host molecules [(1-cyclohexyl-4-hydroxybenzene, 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol, 4-((10-[4-(ethoxycarbonyl)phenoxy]decyl)oxy)benzene, 1,2,4,5-benzenetetracarboxylic acid, resorcinol] and light-sensitive guest molecules [(5-chloro-2(1H)-pyridone or 5-nitro-2(1H)-pyridone] are described in light of their failure to undergo [4 + 4] photodimerization in the solid-state upon irradiation with UV light. Unlike in many cases were pyridone and its derivatives undergo such dimerization in the solid-state due to the packing arrangement in the crystalline form in which the geometric requirement for photodimerization meet, the compounds described here failed to pack in ways to enable such photodimerization. The distances between the potentially reactive atoms ranged from 4.620 to 8.408 ? which are too long to react. 相似文献15.
Vivek D. Bobade Pravin C. Mhaske Kamlesh S. Vadgaonkar Shivaji H. Shelke 《Monatshefte für Chemie / Chemical Monthly》2012,21(4):847-851
Abstract
Efficient utilization of a Mannich-type reaction and the ring-closing metathesis (RCM) approach that leads to a convenient synthesis of 3-(aminomethyl)-5-methylhexanoic acid (pregabalin) is described. 相似文献16.
Xiu-Xiang Yuan Yan-Fang Wang Xin Wang Wenbo Chen John S Fossey Ning-Bew Wong 《Chemistry Central journal》2010,4(1):6
Background
Hydration is a universal phenomenon in nature. The interactions between biomolecules and water of hydration play a pivotal role in molecular biology. 2-Thioxanthine (2TX), a thio-modified nucleic acid base, is of significant interest as a DNA inhibitor yet its interactions with hydration water have not been investigated either computationally or experimentally. Here in, we reported an ab initio study of the hydration of 2TX, revealing water can form seven hydrated complexes. 相似文献17.
Background
Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea. While previously characterized arginases have an alkaline pH optimum and require activation with manganese, arginase from Helicobacter pylori is optimally active with cobalt at pH 6. The arginase from Bacillus anthracis is not well characterized; therefore, this arginase was investigated by a variety of strategies and the enzyme was purified. 相似文献18.
《Rapid communications in mass spectrometry : RCM》2018,32(2):93-104
Rationale
Li and Mg isotopes are increasingly used as a combined tool within the geosciences. However, established methods require separate sample purification protocols utilising several column separation procedures. This study presents a single‐step cation‐exchange method for quantitative separation of trace levels of Li and Mg from multiple sample matrices.Methods
The column method utilises the macro‐porous AGMP‐50 resin and a high‐aspect ratio column, allowing quantitative separation of Li and Mg from natural waters, sediments, rocks and carbonate matrices following the same elution protocol. High‐precision isotope determination was conducted by multi‐collector inductively coupled plasma mass spectrometry (MC‐ICPMS) on the Thermo Scientific™ NEPTUNE Plus™ fitted with 1013 Ω amplifiers which allow accurate and precise measurements at ion beams ≤0.51 V.Results
Sub‐nanogram Li samples (0.3–0.5 ng) were regularly separated (yielding Mg masses of 1–70 μg) using the presented column method. The total sample consumption during isotopic analysis is <0.5 ng Li and <115 ng Mg with long‐term external 2σ precisions of ±0.39‰ for δ7Li and ±0.07‰ for δ26Mg. The results for geological reference standards and seawater analysed by our method are in excellent agreement with published values despite the order of magnitude lower sample consumption.Conclusions
The possibility of eluting small sample masses and the low analytical sample consumption make this method ideal for samples of limited mass or low Li concentration, such as foraminifera, mineral separates or dilute river waters.19.
Abstract
Succinimide sulfonic acid (SuSA) as a stable reagent is easily prepared by the reaction of succinimide with neat chlorosulfonic acid. This compound is able to catalyze the chemoselective conversion of amines to their corresponding N-Boc protected derivatives with (Boc)2O. All reactions were performed under mild conditions, giving the desired products in good to high yields. 相似文献20.
Aejazur Rahman Saumya S Srivastava Amita Sneh Neesar Ahmed Musti V Krishnasastry 《BMC biochemistry》2010,11(1):35