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https://www.readbyqxmd.com/read/29352105/an-ornithine-%C3%AF-aminotransferase-required-for-growth-in-the-absence-of-exogenous-proline-in-the-archaeon-thermococcus-kodakarensis
#1
Ren-Chao Zheng, Shin-Ichi Hachisuka, Hiroya Tomita, Tadayuki Imanaka, Yu-Guo Zheng, Makoto Nishiyama, Haruyuki Atomi
Aminotransferases are pyridoxal 5'-phosphate-dependent enzymes that catalyze reversible transamination reactions between amino acids and α-keto acids, and are important for the cellular metabolism of nitrogen. Many bacterial and eukaryotic ω-aminotransferases that use L-ornithine (Orn), L-lysine (Lys) or γ-aminobutyrate (GABA) have been identified and characterized, but the corresponding enzymes from archaea are unknown. Here we examined the activity and function of TK2101, a gene annotated as GABA aminotransferase, from the hyperthermophilic archaeon Thermococcus kodakarensis We overexpressed the TK2101 gene in T...
January 19, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29346776/loss-of-an-androgen-inactivating-and-isoform-specific-hsd17b4-splice-form-enables-emergence-of-castration-resistant-prostate-cancer
#2
Hyun-Kyung Ko, Michael Berk, Yoon-Mi Chung, Belinda Willard, Rohan Bareja, Mark Rubin, Andrea Sboner, Nima Sharifi
Castration-resistant prostate cancer (CRPC) requires tumors to engage metabolic mechanisms that allow sustained testosterone and/or dihydrotestosterone to stimulate progression. 17β-Hydroxysteroid dehydrogenase type 4 (17βHSD4), encoded by HSD17B4, is thought to inactivate testosterone and dihydrotestosterone by converting them to their respective inert 17-keto steroids. Counterintuitively, HSD17B4 expression increases in CRPC and predicts poor prognosis. Here, we show that, of five alternative splice forms, only isoform 2 encodes an enzyme capable of testosterone and dihydrotestosterone inactivation...
January 16, 2018: Cell Reports
https://www.readbyqxmd.com/read/29345947/nucleophilic-ring-opening-of-donor-acceptor-cyclopropanes-catalyzed-by-a-br%C3%A3-nsted-acid-in-hexafluoroisopropanol
#3
Edward Richmond, Vuk D Vuković, Joseph Moran
A general, Brønsted acid catalyzed method for the room temperature, nucleophilic ring opening of donor-acceptor cyclopropanes in fluorinated alcohol solvent, HFIP, is described. Salient features of this method include an expanded cyclopropane scope, including those bearing single keto-acceptor groups and those bearing electron-deficient aryl groups. Notably, the catalytic system proved amenable to a wide range of nucleophiles including arenes, indoles, azides, diketones, and alcohols.
January 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29345132/rh-iii-catalyzed-acceptorless-dehydrogenative-coupling-of-hetero-arenes-with-2-carboxyl-allylic-alcohols
#4
Jintao Xia, Zhipeng Huang, Xukai Zhou, Xifa Yang, Feng Wang, Xingwei Li
Rhodium(III)-catalyzed C-H activation of (hetero)arenes and redox-neutral coupling with 2-carboxyl allylic alcohols has been realized for the construction of β-aryl ketones. This reaction occurred efficiently at a relatively low catalyst loading via initial dehydrogenative alkylation to give a β-keto carboxylic acid, followed by decarboxylation.
January 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29344298/akr1c1-activates-stat3-to-promote-the-metastasis-of-non-small-cell-lung-cancer
#5
Hong Zhu, Lin-Lin Chang, Fang-Jie Yan, Yan Hu, Chen-Ming Zeng, Tian-Yi Zhou, Tao Yuan, Mei-Dan Ying, Ji Cao, Qiao-Jun He, Bo Yang
Metastasis is the leading cause of mortality for human non-small cell lung cancer (NSCLC). However, it is difficult to target tumor metastasis because the molecular mechanisms underlying NSCLC invasion and migration remain unclear. Methods: GEO data analyses and IHC analyses were performed to identify that the expression level of AKR1C1, a member of human aldo-keto reductase family, was highly elevated in patients with metastasis or metastatic foci of NSCLC patients. Functional analyses (in vitro and in vivo) and quantitative genomic analyses were preformed to confirm the pro-metastatic effects of AKR1C1 and the underlying mechanisms...
2018: Theranostics
https://www.readbyqxmd.com/read/29343522/polyol-pathway-links-glucose-metabolism-to-the-aggressiveness-of-cancer-cells
#6
Annemarie Schwab, Aarif Siddiqui, Maria Eleni Vazakidou, Francesca Napoli, Martin Böttcher, Bianca Menchicchi, Umar Raza, Özge Saatci, Angela M Krebs, Fulvia Ferrazzi, Ida Rapa, Katja Dettmer-Wilde, Maximilian J Waldner, Arif B Ekici, Suhail Ahmed Kabeer Rasheed, Dimitrios Mougiakakos, Peter J Oefner, Özgür Şahin, Marco Volante, Florian R Greten, Thomas Brabletz, Paolo Ceppi
Cancer cells alter their metabolism to support their malignant properties. In this study, we report that the glucose-transforming polyol pathway (PP) gene aldo-keto-reductase-1-member-B1 (AKR1B1) strongly correlates with epithelial-to-mesenchymal transition (EMT). This association was confirmed in samples from lung cancer patients and from an EMT-driven colon cancer mouse model with p53 deletion. In vitro, mesenchymal-like cancer cells showed increased AKR1B1 levels, and AKR1B1 knockdown was sufficient to revert EMT...
January 17, 2018: Cancer Research
https://www.readbyqxmd.com/read/29336673/a-practical-synthesis-of-xylo-and-arabinofuranoside-precursors-by-diastereoselective-reduction-using-corey-bakshi-shibata-catalyst
#7
Lynn M Utley, Jessica Maldonado, Ahmed M Awad
The Corey-Bakshi-Shibata (CBS) catalyst provides an efficient mechanism to reduce ketones and achieve desired enantiopure alcohols. Herein, the diastereoselective reduction of C-2' and C-3'-keto ribofuranoside derivatives to the corresponding arabino- and xylofuranosides in greater than 95% diastereomeric excess is reported. The stereo-directed substitution with an azido group as well as the synthesis of prodrugs cytarabine and vidarabine are also described. The reported strategy offers superior diastereoselectivity, shorter reaction times, and obviates cooling required with comparable protocols involving achiral reductants...
January 16, 2018: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/29332642/current-affairs-future-perspectives-of-tuberculosis-and-antitubercular-agents
#8
REVIEW
Jineetkumar Gawad, Chandrakant Bonde
Tuberculosis (TB) is the major threat for humans from past several decades. Even after advent of several antitubercular drugs, researchers are still struggling for the mycobacterial infections in humans are TB and leprosy. Chronic infections caused by Mycobacterium tuberculosis and Mycobacterium leprae. A particular problem with both of these organisms is that they can survive inside macrophages after phagocytosis, unless these cells are activated by cytokines produced by T-lymphocytes, because of this researchers are not yet succeeded in finding effective treatment on TB...
January 2018: Indian Journal of Tuberculosis
https://www.readbyqxmd.com/read/29330189/targeted-synthesis-and-characterization-of-a-gene-cluster-encoding-nad-p-h-dependent-3%C3%AE-3%C3%AE-and-12%C3%AE-hydroxysteroid-dehydrogenases-from-eggerthella-cag-298-a-gut-metagenomic-sequence
#9
Sean M Mythen, Saravanan Devendran, Celia Méndez-García, Isaac Cann, Jason M Ridlon
Gut metagenomic sequences provide a rich source of microbial genes, the majority of which are annotated by homology or unknown. Genes and gene pathways that encode enzymes catalyzing biotransformation of host bile acids are important to identify in gut metagenomic sequences due to the importance of bile acids on gut microbiome structure and host physiology. Hydroxysteroid dehydrogenases (HSDH) are pyridine nucleotide-dependent enzymes with stereo-specificity and regio-specificity for bile acid and steroid hydroxyl groups...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29328548/copper-catalyzed-oxidative-reaction-of-%C3%AE-keto-sulfones-with-alcohols-via-c-s-bond-cleavage-reaction-development-and-mechanism-study
#10
Bingnan Du, Wenmin Wang, Yang Wang, Zheng-Hang Qi, Jiaqi Tian, Jie Zhou, Xiaochen Wang, Jianlin Han, Jing Ma, Yi Pan
A Cu-catalyzed cascade oxidative radical process of β-keto sulfones with alcohols has been achieved by using oxygen as an oxidant. In this reaction, β-keto sulfones were converted into sulfinate esters under the oxidative conditions via cleavage of C-S bond. Experimental and computational studies demonstrate that a new pathway is involved in this reaction, which proceeds through the formation of the key four-coordinated Cu(II) intermediate, O-O bond homolysis induced C-S bond cleavage and Cu-catalyzed esterification to form the final products...
January 12, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29327817/ketonization-of-proline-residues-in-the-peptide-chains-of-actinomycins-by-a-4-oxoproline-synthase
#11
Siamak Semsary, Ivana Crnovčić, Ronja Driller, Joachim Vater, Bernhard Loll, Ullrich Keller
X-type actinomycins (Acms) contain 4-hydroxyproline (Acm X0) or 4-oxoproline (Acm X2) in their ß-pentapeptide lactone rings whereas their α-ring contains proline. We demonstrate that these Acms are formed through asymmetric condensation of Acm half molecules (Acm halves) containing proline with 4-hydroxyproline- or 4-oxo-proline-containing Acm halves. In turn we show - using an artificial Acm half analogue (PPL 1) with proline in its peptide chain - its conversion into the 4-hydroxyproline and 4-oxoproline-containing Acm halves, PPL 0 and PPL 2, in mycelial suspensions of Streptomyces antibioticus...
January 12, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29324714/determination-of-branched-chain-keto-acids-in-serum-and-muscles-using-high-performance-liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry
#12
You Zhang, Bingjie Yin, Runxian Li, Pingli He
Branched-chain keto acids (BCKAs) are derivatives from the first step in the metabolism of branched-chain amino acids (BCAAs) and can provide important information on animal health and disease. Here, a simple, reliable and effective method was developed for the determination of three BCKAs (α-ketoisocaproate, α-keto-β-methylvalerate and α-ketoisovalerate) in serum and muscle samples using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS). The samples were extracted using methanol and separated on a 1...
January 11, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29323531/an-efficient-gas-chromatography-mass-spectrometry-approach-for-the-simultaneous-analysis-of-deoxynivalenol-and-its-bacterial-metabolites-3-keto-don-and-3-epi-don
#13
Kaijie Tang, Huaizhi Liu, Xiu-Zhen Li, Yousef I Hassan, Suqin Shao, Ting Zhou
Deoxynivalenol (DON) is one of the major toxic secondary metabolites produced by Fusarium fungi in cereal grains. Among the many promising strategies of DON detoxification are the microbial and enzymatic ones, which transform DON to nontoxic DON metabolites. Thus, proper analytical methods are needed for those DON metabolites. In this study, a robust gas chromatography-mass spectrometry (GC-MS) procedure was developed and validated for the simultaneous analysis of DON and two of its bacterial metabolites, 3-keto-DON and 3- epi-DON...
January 11, 2018: Journal of Food Protection
https://www.readbyqxmd.com/read/29323502/regioselective-neighboring-group-participated-2-4-dibromohydration-of-conjugated-enynes-synthesis-of-2-2-4-dibromobut-2-enoyl-benzoate-and-its-applications
#14
Si-Tian Yuan, Hongwei Zhou, Liang Gao, Jin-Biao Liu, Guanyinsheng Qiu
A regioselective 2,4-dibromohydration of conjugated enynes is reported for the synthesis of 2-(2,4-dibromobut-2-enoyl)benzoate. In the presence of tetra-n-butylammonium bromide and H2O the transformation proceeds smoothly with good reaction efficiency and a broad reaction scope. Mechanism studies indicate that the neighboring ester group participates in the 2,4-dibromohydration, and the oxygen atom of ester is transferred into the C-C triple bond to form the keto carbonyl group in the product. 2-(2,4-Dibromobut-2-enoyl)benzoate is recognized as an important synthon toward phthalazin-1(2H)-one and the natural product Shihunine...
January 11, 2018: Organic Letters
https://www.readbyqxmd.com/read/29323483/correction-to-synthesis-of-potent-and-selective-inhibitors-of-aldo-keto-reductase-1b10-and-their-efficacy-against-proliferation-metastasis-and-cisplatin-resistance-of-lung-cancer-cells
#15
Satoshi Endo, Shuang Xia, Miho Suyama, Yoshifumi Morikawa, Hiroaki Oguri, Dawei Hu, Yoshinori Ao, Satoyuki Takahara, Yoshikazu Horino, Yoshihiro Hayakawa, Yurie Watanabe, Hiroaki Gouda, Akira Hara, Kazuo Kuwata, Naoki Toyooka, Toshiyuki Matsunaga, Akira Ikari
No abstract text is available yet for this article.
January 11, 2018: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29321810/metabolic-engineering-of-pichia-pastoris-for-production-of-isobutanol-and-isobutyl-acetate
#16
Wiparat Siripong, Philipp Wolf, Theodora Puspowangi Kusumoputri, Joe James Downes, Kanokarn Kocharin, Sutipa Tanapongpipat, Weerawat Runguphan
Background: Interests in renewable fuels have exploded in recent years as the serious effects of global climate change become apparent. Microbial production of high-energy fuels by economically efficient bioprocesses has emerged as an attractive alternative to the traditional production of transportation fuels. Here, we engineered Pichia pastoris, an industrial workhorse in heterologous enzyme production, to produce the biofuel isobutanol from two renewable carbon sources, glucose and glycerol...
2018: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/29316667/uv-vis-induced-degradation-of-phenol-over-magnetic-photocatalysts-modified-with-pt-pd-cu-and-au-nanoparticles
#17
Izabela Wysocka, Ewa Kowalska, Konrad Trzciński, Marcin Łapiński, Grzegorz Nowaczyk, Anna Zielińska-Jurek
The combination of TiO₂ photocatalyst and magnetic oxide nanoparticles enhances the separation and recoverable properties of nanosized TiO₂ photocatalyst. Metal-modified (Me = Pd, Au, Pt, Cu) TiO₂/SiO₂@Fe₃O₄ nanocomposites were prepared by an ultrasonic-assisted sol-gel method. All prepared samples were characterized by X-ray powder diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), Mott-Schottky analysis and photoluminescence spectroscopy (PL)...
January 7, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29315969/effectiveness-of-interventions-to-decrease-image-ordering-for-low-back-pain-presentations-in-the-emergency-department-a-systematic-review
#18
Chaocheng Liu, Shashwat Desai, Lynette D Krebs, Scott W Kirkland, Diana Keto-Lambert, Brian H Rowe
BACKGROUND: Low back pain (LBP) is an extremely frequent reason for patients to present to an emergency department (ED). Despite evidence against the utility of imaging, simple and advanced imaging (i.e., computed tomography [CT], magnetic resonance imaging [MRI]) for patients with LBP has become increasingly frequent in the ED. The objective of this review was to identify and examine the effectiveness of interventions aimed at reducing image ordering in the ED for LBP patients. METHODS: A protocol was developed a priori, following the PRISMA guidelines, and registered with PROSPERO...
January 8, 2018: Academic Emergency Medicine: Official Journal of the Society for Academic Emergency Medicine
https://www.readbyqxmd.com/read/29314710/different-in-vitro-and-in-vivo-tools-for-elucidating-the-human-metabolism-of-alpha-cathinone-derived-drugs-of-abuse
#19
Sascha K Manier, Lilian H J Richter, Jan Schäper, Hans H Maurer, Markus R Meyer
In vitro and in vivo experiments are widely used for studying the metabolism of new psychoactive substances (NPS). The availability of such data is required for toxicological risk assessments and development of urine screening approaches. This study investigated the in vitro metabolism of the five pyrrolidinophenone-derived NPS alpha-pyrrolidinobutyrophenone (alpha-PBP), alpha-pyrrolidinopentiothiophenone (alpha-PVT), alpha-pyrrolidinohexanophenone (alpha-PHP), alpha-pyrrolidinoenanthophenone (alpha-PEP, PV8), and alpha-pyrrolidinooctanophenone (alpha-POP, PV9)...
January 4, 2018: Drug Testing and Analysis
https://www.readbyqxmd.com/read/29307017/clinical-characteristics-and-mutation-analysis-of-five-chinese-patients-with-maple-syrup-urine-disease
#20
Xiaomei Li, Yali Yang, Qing Gao, Min Gao, Yvqiang Lv, Rui Dong, Yi Liu, Kaihui Zhang, Zhongtao Gai
Maple syrup urine disease (MSUD) is an autosomal recessive disorder affecting branched-chain amino acids (BCAAs) metabolism and caused by a defect in the thiamine-dependent enzyme branched chain α-ketoacid dehydrogenase (BCKD) with subsequent accumulation of BCAAs and corresponding branched-chain keto acids (BCKAs) metabolites. Presently, at least 4 genes of BCKDHA, BCKDHB, DLD and DBT have been reported to cause MSUD. Furthermore, more than 265 mutations have been identified as the cause across different populations worldwide...
January 6, 2018: Metabolic Brain Disease
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