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indole hydroxylation

Heather R Williamson, Esha Sehanobish, Alan M Shiller, Antonio Sanchez-Amat, Victor L Davidson
The first posttranslational modification step in the biosynthesis of the tryptophan-derived quinone cofactors is the autocatalytic hydroxylation of a specific Trp residue at position C-7 on the indole side chain. Subsequent modifications are catalyzed by modifying enzymes, but the mechanism by which this first step occurs is unknown. LodA possesses a cysteine tryptophylquinone (CTQ) cofactor. Metal analysis as well as spectroscopic and kinetic studies of the mature and precursor forms of a D512A LodA variant provides evidence that copper is required for the initial hydroxylation of the precursor protein and that if alternative metals are bound, the modification does not occur and the precursor is unstable...
February 21, 2017: Biochemistry
Qian Wu, Dingyuan Yan, Ying Chen, Ting Wang, Feng Xiong, Wei Wei, Yi Lu, Wei-Yin Sun, Jie Jack Li, Jing Zhao
Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source...
January 27, 2017: Nature Communications
Xiangcong Wang, Maocai Yan, Qibao Wang, Huannan Wang, Zhengyang Wang, Jiayi Zhao, Jing Li, Zhen Zhang
Indole-2-carboxylic acid copper complex (ICA-Cu) was successfully prepared and characterized through elemental analysis, IR, UV-Vis, ¹H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu₂(C₉H₆O₂N)₄(H₂O)₂]·2H₂O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA) was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength...
January 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Tushar S Basu Baul, Pelesakuo Kehie, Andrew Duthie, Nikhil Guchhait, Nune Raviprakash, Raveendra B Mokhamatam, Sunil K Manna, Nerina Armata, Michelangelo Scopelliti, Ruimin Wang, Ulli Englert
Five new organotin(IV) complexes of compositions [Me2SnL(1)] (1), [Me2SnL(2)]n (2), [Me2SnL(3)] (3), [Ph3SnL(1)H]n (4) and [Ph3SnL(3)H] (5) (where L(1)=(2S)-2-((E)-((Z)-4-hydroxypent-3-en-2-ylidene)amino)-3-(1H-indol-3-yl)propanoate, L(2)=(2S)-(E)-2-((2-hydroxybenzylidene)amino)-3-(1H-indol-3-yl)propanoate and L(3)=(2S)-(E)-2-((1-(2-hydroxyphenyl)ethylidene)amino)-3-(1H-indol-3-yl)propanoate were synthesized and spectroscopically characterized. The crystal structures of 1-4 were determined. For the dimethyltin derivative 2, a polymeric chain structure was observed as a result of a long Sn∙∙∙O contact involving the exocyclic carbonyl oxygen-atom from the tridentate ligand of a neighboring Sn-complex unit...
December 16, 2016: Journal of Inorganic Biochemistry
Yang Qu, Razvan Simonescu, Vincenzo De Luca
Two new monoterpene indole alkaloids, isoakuammiline (1) and 18-hydroxypseudovincadifformine (2), and five known alkaloids, coronaridine (3), heyneanine (4), 3,19-oxidocoronaridine (5), tabersonine, and strictosidine, were identified from the fruit of Tabernaemontana litoralis. The structures of the alkaloids were determined using NMR and MS data analyses. While 18-hydroxypseudovincadifformine (2) showed a new hydroxylation pattern, isoakuammiline (1) revealed a novel skeleton for monoterpene indole alkaloids...
December 23, 2016: Journal of Natural Products
Di Zhou, Yuhua Zhang, Zhe Jiang, Yue Hou, Kun Jiao, Chunyan Yan, Ning Li
Isofraxetin-6-O-β-d-glucopyranoside, identified from traditional medicinal herbal Xanthoceras sorbifolia Bunge, has been demonstrated to be a natural neuroinflammatory inhibitor. In order to obtain more derivatives with potential anti-neuroinflammatory effects, biotransformation was carried out. According to the characteristics of coumarin skeleton, suspension cultures of Angelica sinensis (Oliv.) Diels callus (A. sinensis callus) were employed because of the presence of diverse phenylpropanoids biosynthetic enzymes...
January 15, 2017: Bioorganic & Medicinal Chemistry Letters
Marina Pfalz, Maisara Mukhaimar, François Perreau, Jayne Kirk, Cecilie Ida Cetti Hansen, Carl Erik Olsen, Niels Agerbirk, Juergen Kroymann
Indole glucosinolates (IGs) are plant secondary metabolites that are derived from the amino acid tryptophan. The product of Arabidopsis (Arabidopsis thaliana) IG core biosynthesis, indol-3-ylmethyl glucosinolate (I3M), can be modified by hydroxylation and subsequent methoxylation of the indole ring in position 1 (1-IG modification) or 4 (4-IG modification). Products of the 4-IG modification pathway mediate plant-enemy interactions and are particularly important for Arabidopsis innate immunity. While CYP81Fs encoding cytochrome P450 monooxygenases and IGMTs encoding indole glucosinolate O-methyltransferases have been identified as key genes for IG modification, our knowledge about the IG modification pathways is not complete...
December 2016: Plant Physiology
Stefania Ferro, Laura De Luca, Maria Paola Germanò, Maria Rosa Buemi, Laura Ielo, Giovanna Certo, Margarita Kanteev, Ayelet Fishman, Antonio Rapisarda, Rosaria Gitto
Tyrosinase is involved in the production of melanin through the hydroxylation of monophenols to o-diphenols. The role of this enzyme was extensively studied in order to identify new therapeutics preventing skin pigmentation and melanoma. In this work we initially identified the 3-(4-benzylpiperidin-1-yl)-1-(1H-indol-3-yl)propan-1-one (1a) as promising mushroom tyrosinase inhibitor (IC50 = 252 μM). Then, several chemical modifications were performed and new analogues related to compound 1a were synthesized...
January 5, 2017: European Journal of Medicinal Chemistry
Cuixia Gao, Bingxian Yang, Dandan Zhang, Meng Chen, Jingkui Tian
BACKGROUND: Indole alkaloids, which characteristically contain an indole nucleus, have pharmaceutical potential in a diverse range of applications. UV-B can elicit the accumulation of indole alkaloids. The indole alkaloid (6-hydroxyl-1H-indol-3-yl) carboxylic acid methyl ester with cytotoxic activity was found to accumulate in Clematis terniflora DC. leaves after exposure to high level of UV-B irradiation and the dark. However, a more in-depth analysis of the process behind this response has not yet been performed...
October 24, 2016: BMC Plant Biology
Chantal Cossette, Shishir Chourey, Qiuji Ye, Chintam Nagendra Reddy, Vivek Gore, Sylvie Gravel, Irina Slobodchikova, Dajana Vuckovic, Joshua Rokach, William S Powell
The potent eosinophil chemoattractant 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) is a 5-lipoxygenase product that acts via the selective OXE receptor, which is present in many species, but not rodents. We previously reported that the indole 230 is a potent human OXE receptor antagonist. The objective of the present study was to determine whether the monkey would be a suitable animal model to investigate its pharmaceutical potential. We found that monkey leukocytes synthesize and respond to 5-oxo-ETE and that 230 is a potent antagonist of the OXE receptor in monkey eosinophils...
November 23, 2016: Journal of Medicinal Chemistry
Carl Erik Olsen, Xiao-Chen Huang, Cecilie I C Hansen, Don Cipollini, Marian Ørgaard, Annemarie Matthes, Fernando Geu-Flores, Marcus A Koch, Niels Agerbirk
As a basis for future investigations of evolutionary trajectories and biosynthetic mechanisms underlying variations in glucosinolate structures, we screened members of the crucifer tribe Cardamineae by HPLC-MS/MS, isolated and identified glucosinolates by NMR, searched the literature for previous data for the tribe, and collected HPLC-MS/MS data for nearly all glucosinolates known from the tribe as well as some related structures (70 in total). This is a considerable proportion of the approximately 142 currently documented natural glucosinolates...
December 2016: Phytochemistry
Chengwei Liu, Atsushi Minami, Tohru Dairi, Katsuya Gomi, Barry Scott, Hideaki Oikawa
The late-stage biosynthetic pathway of the indole diterpene shearinine involving four enzymatic reactions (JanQDOJ) was elucidated by an efficient heterologous expression system using Aspergillus oryzae. Key oxidative cyclization, forming a characteristic A/B bicyclic shearinine core by flavoprotein oxidase, was studied using a substrate analogue and a buffer containing H2(18)O. These experimental data provided evidence that JanO catalyzes two-step oxidation via a hydroxylated product and that the JanO reaction involves the hydride-transfer mechanism...
October 7, 2016: Organic Letters
Andrzej T Slominski, Igor Semak, Tobias W Fischer, Tae-Kang Kim, Konrad Kleszczyński, Ruediger Hardeland, Russel J Reiter
Melatonin is produced in almost all living taxa and is probaly 2-3 billion years old. Its pleiotropic activities are related to its local concentration that is secondary to its local synthesis, delivery from distant sites and metabolic or non-enzymatic consumption. This consumption generates metabolites through indolic, kynuric and cytochrome P450 (CYP) mediated hydroxylations and O-demethylation or non-enzymatic processes, with potentially diverse phenotypic effects. While melatonin acts through receptor dependent and independent mechanism, receptors for melatonin metabolites remain to be identified, while their receptor independent activities are well documented...
September 13, 2016: Experimental Dermatology
Florian Franz, Verena Angerer, Bjoern Moosmann, Volker Auwärter
Among the recently emerged synthetic cannabinoids, MDMB-CHMICA (methyl N-{[1-(cyclohexylmethyl)-1H-indol-3-yl]carbonyl}-3-methylvalinate) shows an extraordinarily high prevalence in intoxication cases, necessitating analytical methods capable of detecting drug uptake. In this study the in vivo phase I metabolism of MDMB-CHMICA was investigated using LC-ESI-MS/MS and LC-ESI-Q-ToF-MS techniques. The main metabolites are formed by hydrolysis of the methyl ester and oxidation of the cyclohexyl methyl side chain...
August 9, 2016: Drug Testing and Analysis
Yusuke Amino
Monatin, 4-hydroxy-4-(3-indolylmethyl)-glutamic acid, is a naturally occurring sweet amino acid. The (2R,4R)-monatin isomer has been found to be the sweetest among its four stereoisomers. A concise and efficient synthesis of (2R,4R)-monatin was accomplished by the alkylation of (4R)-N-tert-butoxycarbonyl (tBoc)-4-tert-butyldimethylsilyoxy-D-pyroglutamic acid methyl ester with tert-butyl 3-(bromomethyl)-1H-indole-1-carboxylate to give (4R)-N-tBoc-4-tert-butyldimethylsilyloxy-4-(N-tBoc-3-indolylmethyl)-D-pyroglutamic acid methyl ester, i...
2016: Chemical & Pharmaceutical Bulletin
Nadine Schaefer, Andreas G Helfer, Mattias Kettner, Matthias W Laschke, Julia Schlote, Andreas H Ewald, Markus R Meyer, Michael D Menger, Hans H Maurer, Peter H Schmidt
The knowledge of pharmacokinetic (PK) properties of synthetic cannabinoids (SCs) is important for interpretation of analytical results found for example in intoxicated individuals. In the absence of human data from controlled studies, animal models elucidating SC PK have to be established. Pigs providing large biofluid sample volumes were tested for prediction of human PK data. In this context, the metabolic fate of two model SCs, namely 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210) and 2-(4-methoxyphenyl)-1-(1-pentyl-indol-3-yl)methanone (RCS-4), was elucidated in addition to Δ(9) -tetrahydrocannabinol (THC)...
June 22, 2016: Drug Testing and Analysis
J Enríquez, R Velázquez-Cruz, A Parra-Torres, R Gutiérrez-Sagal, F Larrea
PURPOSE: To gain new insight into the roles of cruciferous vegetable-derived bioactive phytochemicals in bone cells, we investigated the effects of indole-3-carbinol (I3C) on cell proliferation and differentiation in estradiol (E2)-exposed calvarial osteoblasts that were obtained from neonatal rats. METHODS: Osteoblast activity was assessed by analyzing cellular DNA, cell-associated osteocalcin (OC) levels and alkaline phosphatase (AP) activity. We also examined [(3)H]-estrone (E1) metabolism and estrogen-agonistic and estrogen-antagonistic activities of 2-hydroxy (OH) E1 and 2-OHE2 and their capacity to displace [(3)H]-E2 at ER binding sites using competition studies...
October 2016: Journal of Endocrinological Investigation
Kang Zhou, Wei Zhao, Xiao-Qing Liu, Shu-Ming Li
The fungal indole prenyltransferase FtmPT1 is involved in the biosynthesis of fumitremorgins and catalyzes, in the presence of dimethylallyl diphosphate, a predominant regular prenylation of cyclo-L-Trp-L-Pro (brevianamide F) at position C-2 of the indole nucleus. Analysis of the substrate-bound structure of FtmPT1 revealed that brevianamide F forms a hydrogen bond via its carbonyl oxygen in the diketopiperazine moiety with the hydroxyl group of Tyr205 near the center of the prenyltransferase (PT) barrel. In this study, Tyr205 was mutated to 19 other proteinogenic amino acids by one-step site-directed mutagenesis...
December 2016: Applied Microbiology and Biotechnology
Maiko Kusano, Kei Zaitsu, Mayumi Yamanaka, Kazuaki Hisatsune, Tomomi Asano, Kentaro Taki, Yumi Hayashi, Hitoshi Tsuchihashi, Akira Ishii
One of the many issues of designer drugs of abuse like synthetic cannabinoids (SCs) such as JWH-018 is that details on their metabolism has yet to be fully elucidated and that multiple metabolites exist. The presence of isomeric compounds poses further challenges in their identification. Our group has previously shown the effectiveness of gas chromatography-electron ionization-tandem mass spectrometry (GC-EI-MS/MS) in the mass spectrometric differentiation of the positional isomers of the naphthoylindole-type SC JWH-081, and speculated that the same approach could be used for the metabolite isomers...
May 2016: Journal of Mass Spectrometry: JMS
Martin Wilke, Christian Brand, Josefin Wilke, Michael Schmitt
The 5-hydroxytryptamine receptors (5HTn) are optimized for 5-hydrotryptamine molecules, resulting in a significantly enhanced psychoactive response compared with the 4-, 6-, 7-isomers. This is despite their relatively similar energetic stabilities, excited state lifetimes and emission characteristics. In this work we investigate the conformational space of serotonin (5-hydroxytryptamine) using a combination of rotationally resolved electronic spectroscopy and ab initio calculations. The geometries of the four most abundant conformers are assigned from their molecular parameters in the electronic ground and excited state...
May 11, 2016: Physical Chemistry Chemical Physics: PCCP
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