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https://www.readbyqxmd.com/read/28653705/esipt-active-organic-compounds-with-white-luminescence-based-on-crystallization-induced-keto-emission-cike
#1
Huapeng Liu, Xiao Cheng, Houyu Zhang, Yue Wang, Hongyu Zhang, Shigehiro Yamaguchi
Structurally simple pyrazole derivatives that exhibit excited-state intramolecular proton transfer (ESIPT) were synthesized. While these compounds displayed deep violet fluorescence in solution, in the crystalline state they showed white emission from the enol and keto forms.
June 27, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28652076/radical-trapping-and-preventive-antioxidant-effects-of-2-hydroxymelatonin-and-4-hydroxymelatonin-contributions-to-the-melatonin-protection-against-oxidative-stress
#2
Adriana Pérez-González, Annia Galano, J Raúl Alvarez-Idaboy, Dun Xian Tan, Russel J Reiter
BACKGROUND: Melatonin is well known for its antioxidant capacity, which has been attributed to the combined protective effects of the parent molecule and its metabolites. However, the potential role of 2-hydroxymelatonin (2OHM) and 4-hydroxymelatonin (4OHM) in such protection has not been previously investigated. METHODS: The calculations were performed using the Density Functional Theory, with the M05-2× and M05 functionals, the 6-311+G(d,p) basis set and the solvation model based on density (SMD)...
June 23, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28651911/conformational-studies-of-gram-negative-bacterial-quorum-sensing-3-oxo-n-acyl-homoserine-lactone-molecules
#3
Darren Crowe, Alan Nicholson, Adrienne Fleming, Ed Carey, Goar Sánchez-Sanz, Fintan Kelleher
In their (1)H NMR spectra in CDCl3 3-oxo-N-acyl homoserine lactones (OHLs) show significant downfield chemical shifts of the amide NH proton when compared to the parent N-acyl homoserine lactones (AHLs). NMR spectroscopic and DFT calculation studies have shown that this is most likely due to the presence of a stabilising intramolecular H-bond from the NH to the 3-oxo group. The (1)H NMR spectra also show evidence for the enol tautomers and that the amount of enol present for a range of OHLs is 4.1-4.5% in CDCl3 and 6...
June 8, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28651148/aldo-keto-reductase-activity-after-diethylhexyl-phthalate-exposure-in-eutopic-and-ectopic-endometrial-cells
#4
La Yeon Kim, Mee Ran Kim, Jang Heub Kim, Hyun Hee Cho
OBJECTIVE: Endometriosis is a multifactorial gynaecological disease in reproductive-age women. Endometriotic tissue is characterized by high prostaglandin levels and progesterone resistance. Human aldo-keto reductases (AKRs) convert progesterone to a less potent metabolite and cause progesterone resistance. Therefore, in this study, we evaluated whether diethylhexyl phthalate (DEHP) alters AKR expression in human ectopic and eutopic endometrium. STUDY DESIGN: We used microarrays and western blotting to study the effects of DEHP, and checked the presence of AKR in endometriosis patients by enzyme-linked immunosorbent assay (ELISA)...
May 22, 2017: European Journal of Obstetrics, Gynecology, and Reproductive Biology
https://www.readbyqxmd.com/read/28648378/steroidogenic-metabolism-of-galeterone-reveals-a-diversity-of-biochemical-activities
#5
Mohammad Alyamani, Zhenfei Li, Michael Berk, Jianneng Li, Jingjie Tang, Sunil Upadhyay, Richard J Auchus, Nima Sharifi
Galeterone is a steroidal CYP17A1 inhibitor, androgen receptor (AR) antagonist, and AR degrader, under evaluation in a phase III clinical trial for castration-resistant prostate cancer (CRPC). The A/B steroid ring (Δ(5),3β-hydroxyl) structure of galeterone is identical to that of cholesterol, which makes endogenous steroids with the same structure (e.g., dehydroepiandrosterone and pregnenolone) substrates for the enzyme 3β-hydroxysteroid dehydrogenase (3βHSD). We found that galeterone is metabolized by 3βHSD to Δ(4)-galeterone (D4G), which is further converted by steroid-5α-reductase (SRD5A) to 3-keto-5α-galeterone (5αG), 3α-OH-5α-galeterone, and 3β-OH-5α-galeterone; in vivo it is also converted to the three corresponding 5β-reduced metabolites...
June 19, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28646170/triphenyltin-recognition-by-primary-structures-of-effector-proteins-and-the-protein-network-of-bacillus-thuringiensis-during-the-triphenyltin-degradation-process
#6
Linlin Wang, Jinshao Ye, Huase Ou, Huaming Qin, Yan Long, Jing Ke
Herein, triphenyltin (TPT) biodegradation efficiency and its transformation pathway have been elucidated. To better understand the molecular mechanism of TPT degradation, the interactions between amino acids, primary structures, and quaternary conformations of effector proteins and TPT were studied. The results verified that TPT recognition and binding depended on amino acid sequences but not on secondary, tertiary or quaternary protein structure. During this process, TPT could change the molecular weight and isoelectric point of effector proteins, induce their methylation or demethylation, and alter their conformation...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28646078/stereospecific-metabolism-of-r-and-s-warfarin-by-human-hepatic-cytosolic-reductases
#7
Dustyn A Barnette, Bryce Johnson, Dakota L Pouncey, Robert Nshimiyimana, Linda Desrochers, Thomas E Goodwin, Grover Paul Miller
Coumadin (rac-warfarin) is the most commonly used anticoagulant in the world, yet its clinical use is often challenging due to a narrow therapeutic range and inter-individual variations in response. A critical contributor to the uncertainty is variability in warfarin metabolism, which includes mostly oxidative but also reductive pathways. Reduction of each warfarin enantiomer yields two warfarin alcohol isomers, and the corresponding four alcohols retain varying levels of anticoagulant activity. Studies on the kinetics of warfarin reduction have often lacked resolution of parent drug enantiomers and suffered from co-elution of pairs of alcohol metabolites; thus, those studies fail to establish the importance of individual, stereospecific reductive pathways...
June 23, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28645733/low-interleukin-2-concentration-favors-generation-of-early-memory-t-cells-over-effector-phenotypes-during-chimeric-antigen-receptor-t-cell-expansion
#8
Tanja Kaartinen, Annu Luostarinen, Pilvi Maliniemi, Joni Keto, Mikko Arvas, Heini Belt, Jonna Koponen, Petri I Mäkinen, Angelica Loskog, Satu Mustjoki, Kimmo Porkka, Seppo Ylä-Herttuala, Matti Korhonen
No abstract text is available yet for this article.
June 20, 2017: Cytotherapy
https://www.readbyqxmd.com/read/28644714/genome-mining-in-silico-validation-and-phase-selection-of-a-novel-aldo-keto-reductase-from-candida-glabratea-for-biotransformation
#9
Souvik Basak, Nanda Gopal Sahoo, Angayar K Pavanasam
Previously, we published cloning, over-expression, characterization and subsequent exploitation of a carbonyl reductase (cr) gene, belonging to general family aldo-keto reductase from Candida glabrata CBS138 to convert keto ester (COBE) to a chiral alcohol (ethyl-4-chloro-3-hydroxybutanoate or CHBE). Exploiting global transcription factor CRP, rDNA and transporter engineering, we have improved batch production of CHBE by trinomial bioengineering. Herein, we present the exploration of cr gene in Candida glabrata CBS138 through genome miningapproach, in silico validation of its activity and selection of its biocatalytic phase...
June 23, 2017: Bioengineered
https://www.readbyqxmd.com/read/28643829/efficient-scavenging-of-criegee-intermediates-on-water-by-surface-active-cis-pinonic-acid
#10
Shinichi Enami, A J Colussi
cis-Pinonic acid (CPA), the main product of the atmospheric oxidation of biogenic α-pinene emissions and a major component of secondary organic aerosol (SOA), is a potentially key species en route to extremely low volatility compounds. Here, we report that CPA is an exceptionally efficient scavenger of Criegee intermediates (CIs) on aqueous surfaces. Against expectations, millimolar CPA (a surface-active C10 keto-carboxylic acid possessing a rigid skeleton) is able to compete with 23 M bulk water for the CIs produced in the ozonolysis of sesquiterpene solutes by O3(g) on the surface of a water:acetonitrile solvent...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28642838/adaptive-pathways-and-emerging-strategies-overcoming-treatment-resistance-in-castration-resistant-prostate-cancer
#11
Cameron M Armstrong, Allen C Gao
The therapies available for prostate cancer patients whom progress from hormone-sensitive to castration resistant prostate cancer include both systemic drugs, including docetaxel and cabazitaxel, and drugs that inhibit androgen signaling such as enzalutamide and abiraterone. Unfortunately, it is estimated that up to 30% of patients have primary resistance to these treatments and over time even those who initially respond to therapy will eventually develop resistance and their disease will continue to progress regardless of the presence of the drug...
October 2016: Asian Journal of Urology
https://www.readbyqxmd.com/read/28639651/ru-catalyzed-highly-diastereoselective-hydrogenation-of-n-tert-butylsulfinyl-ketimines-for-the-synthesis-of-aryl-glycine-derivatives
#12
Qiaoling Wei, Feng Zhang, Xiaofang Zhao, Chao Wang, Jianliang Xiao, Weijun Tang
A ruthenium pincer catalyst has been shown to be highly efficient for the hydrogenation of a wide range of α-ketimino esters derived from α-keto esters and chiral 2-methylpropyl-2-sulfinamide, affording chiral aryl glycine derivatives with high yields and diasteroselectivities (20 examples, dr values up to 99 : 1).
June 22, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28638776/synthetic-approaches-for-the-preparation-of-phosphoramidate-prodrugs-of-2-deoxypseudoisocytidine
#13
Michaela Serpi, Roberto De Biasi, Fabrizio Pertusati, Magdalena Slusarczyk, Christopher McGuigan
A synthetic procedure for the preparation of phosphoramidate prodrugs of C-nucleosides is reported. Different phosphorochloridates were reacted with 3'-O-protected N-acetyl-2'-deoxypseudoisocytidine or 3'-O-protected 2'-deoxypseudoisocytidine, followed by acidic hydrolysis of the protecting group. In the presence of the N-acetyl moiety, the enolisable keto group of the nucleobase was able to react (like the 5'-OH) with the phosphorochloridates to give bisphosphorylated derivatives. Epimerisation (β to α) occurred if the amino group of the nucleobase was unprotected...
June 2017: ChemistryOpen
https://www.readbyqxmd.com/read/28638047/semi-rational-engineering-of-a-thermostable-aldo-keto-reductase-from-thermotoga-maritima-for-synthesis-of-enantiopure-ethyl-2-hydroxy-4-phenylbutyrate-ehpb
#14
Zhiguo Wang, Shuo Zhou, Shuangling Zhang, Sa Zhang, Fangmeng Zhu, Xiaolu Jin, Zhenming Chen, Xiaoling Xu
A novel aldo-keto reductase Tm1743 characterized from Thermotoga maritima was explored as an effective biocatalyst in chiral alcohol production. Natural Tm1743 catalyzes asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate (EOPB) at high efficiency, but the production of, ethyl (S)-2-hydroxy-4-phenylbutyrate ((S)-EHPB), which is less desirable, is preferred with an enantiomeric excess (ee) value of 76.5%. Thus, altering the enantioselectivity of Tm1743 to obtain the more valuable product (R)-EHPB for angiotensin drug synthesis is highly desired...
June 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28636366/oxygenation-via-c-h-c-c-bond-activation-with-molecular-oxygen
#15
Yu-Feng Liang, Ning Jiao
The selective oxidation of organic molecules is a fundamentally important component of modern synthetic chemistry. In the past decades, direct oxidative C-H and C-C bond functionalization has proved to be one of the most efficient and straightforward methods to synthesize complex products from simple and readily available starting materials. Among these oxidative processes, the use of molecular oxygen as a green and sustainable oxidant has attracted considerable attention because of its highly atom-economical, abundant, and environmentally friendly characteristics...
June 21, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28633109/endothelial-nlrp3-inflammasome-activation-and-arterial-neointima-formation-associated-with-acid-sphingomyelinase-during-hypercholesterolemia
#16
Saisudha Koka, Min Xia, Yang Chen, Owais M Bhat, Xinxu Yuan, Krishna M Boini, Pin-Lan Li
The NLRP3 inflammasome has been reported to be activated by atherogenic factors, whereby endothelial injury and consequent atherosclerotic lesions are triggered in the arterial wall. However, the mechanisms activating and regulating NLRP3 inflammasomes remain poorly understood. The present study tested whether acid sphingomyelinase (ASM) and ceramide associated membrane raft (MR) signaling platforms contribute to the activation of NLRP3 inflammasomes and atherosclerotic lesions during hypercholesterolemia. We found that 7-ketocholesterol (7-Keto) or cholesterol crystal (ChC) markedly increased the formation and activation of NLRP3 inflammasomes in mouse carotid arterial endothelial cells (CAECs), as shown by increased colocalization of NLRP3 with ASC or caspase-1, enhanced caspase-1 activity and elevated IL-1β levels, which were markedly attenuated by mouse Asm siRNA, ASM inhibitor- amitriptyline, and deletion of mouse Asm gene...
June 15, 2017: Redox Biology
https://www.readbyqxmd.com/read/28631488/synthesis-of-6-7-dideoxysqualestatin-h5-by-carbonyl-ylide-cycloaddition-rearrangement-and-cross-electrophile-coupling
#17
Younes Fegheh-Hassanpour, Tanzeel Arif, Herman O Sintim, Hamad H Al Mamari, David M Hodgson
An asymmetric synthesis of (-)-6,7-dideoxysqualestatin H5 is reported. Key features of the synthesis include the following: (1) highly diastereoselective n-alkylation of a tartrate acetonide enolate and subsequent oxidation-hydrolysis to provide an asymmetric entry to a β-hydroxy-α-ketoester motif; (2) facilitation of Rh(II)-catalyzed cyclic carbonyl ylide formation-cycloaddition by co-generation of keto and diazo functionality through ozonolysis of an unsaturated hydrazone; and (3) stereoretentive Ni-catalyzed Csp(3)-Csp(2) cross-electrophile coupling between tricarboxylate core and unsaturated side chain to complete the natural product...
June 20, 2017: Organic Letters
https://www.readbyqxmd.com/read/28631071/oxidation-of-c18-hydroxy-polyunsaturated-fatty-acids-to-epoxide-or-ketone-by-catalase-related-hemoproteins-activated-with-iodosylbenzene
#18
Tarvi Teder, William E Boeglin, Alan R Brash
Small catalase-related hemoproteins with a facility to react with fatty acid hydroperoxides were examined for their potential mono-oxygenase activity when activated using iodosylbenzene. The proteins tested were a Fusarium graminearum 41 kD catalase hemoprotein (Fg-cat, gene FGSG_02217), a Pseudomonas fluorescens Pfl01 catalase (37.5 kD, accession number WP_011333788.1), and a Mycobacterium avium ssp. paratuberculosis 33 kD catalase (gene MAP-2744c). 13-Hydroxy-octadecenoic acids (which are normally unreactive) were selected as substrates because these enzymes react specifically with the corresponding 13S-hydroperoxides (Pakhomova et al...
June 19, 2017: Lipids
https://www.readbyqxmd.com/read/28630872/effect-of-regular-aerobic-activity-in-young-healthy-athletes-on-profile-of-endothelial-function-and-platelet-activity
#19
Katarzyna Podgórska, Arkadiusz Derkacz, Ewa Szahidewicz-Krupska, Jakub Jasiczek, Piotr Dobrowolski, Aneta Radziwon-Balicka, Robert Skomro, Andrzej Szuba, Grzegorz Mazur, Adrian Doroszko
The aim of the study was to assess the impact of regular professional sports activity on the endothelial and platelet function in young men. The studied group were 79 young men (18-40 y, 25 athletes and 54 without any regular physical activity). The nitric oxide (NO) metabolic pathway intermediates, oxidative stress markers, mediators of inflammation, and platelet aggregation were measured. Flow mediated dilation (FMD) was studied before and after intravenous 16,0 g L-arginine infusion, which was repeated after oral administration of acetylsalicylic acid (ASA-75 mg/day) for 4 days...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28628204/a-high-throughput-process-for-the-solid-phase-purification-of-synthetic-dna-sequences
#20
Andrzej Grajkowski, Jacek Cieślak, Serge L Beaucage
An efficient process for the purification of synthetic phosphorothioate and native DNA sequences is presented. The process is based on the use of an aminopropylated silica gel support functionalized with aminooxyalkyl functions to enable capture of DNA sequences through an oximation reaction with the keto function of a linker conjugated to the 5'-terminus of DNA sequences. Deoxyribonucleoside phosphoramidites carrying this linker, as a 5'-hydroxyl protecting group, have been synthesized for incorporation into DNA sequences during the last coupling step of a standard solid-phase synthesis protocol executed on a controlled pore glass (CPG) support...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
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