- Competence of Thiamin Diphosphate-Dependent Enzymes with 2′-Methoxythiamin Diphosphate Derived from Bacimethrin, a Naturally Occurring Thiamin Anti-vitamin
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Bacimethrin (4-amino-5-hydroxymethyl-2-methoxypyrimidine), a natural product isolated from some bacteria, has been implicated as an inhibitor of bacterial and yeast growth, as well as in inhibition of thiamin biosynthesis. Given that thiamin biosynthetic enzymes could convert bacimethrin to 2′-methoxythiamin diphosphate (MeOThDP), it is important to evaluate the effect of this coenzyme analogue on thiamin diphosphate (ThDP)-dependent enzymes. The potential functions of MeOThDP were explored on five ThDP-dependent enzymes: the human and Escherichia coli pyruvate dehydrogenase complexes (PDHc-h and PDHc-ec, respectively), the E. coli 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), and the human and E. coli 2-oxoglutarate dehydrogenase complexes (OGDHc-h and OGDHc-ec, respectively). Using several mechanistic tools (fluorescence, circular dichroism, kinetics, and mass spectrometry), it was demonstrated that MeOThDP binds in the active centers of ThDP-dependent enzymes, however, with a binding mode different from that of ThDP. While modest activities resulted from addition of MeOThDP to E. coli PDHc (6-11%) and DXPS (9-14%), suggesting that MeOThDP-derived covalent intermediates are converted to the corresponding products (albeit with rates slower than that with ThDP), remarkably strong activity (up to 75%) resulted upon addition of the coenzyme analogue to PDHc-h. With PDHc-ec and PDHc-h, the coenzyme analogue could support all reactions, including communication between components in the complex. No functional substitution of MeOThDP for ThDP was in evidence with either OGDH-h or OGDH-ec, shown to be due to tight binding of ThDP.
- Nemeria, Natalia S.,Shome, Brateen,Decolli, Alicia A.,Heflin, Kathryn,Begley, Tadhg P.,Meyers, Caren Freel,Jordan, Frank
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- Differences in the efficiency of 3-deazathiamine and oxythiamine pyrophosphates as inhibitors of pyruvate dehydrogenase complex and growth of HeLa cells in?vitro
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Oxythiamine (OT) and 3-deazathiamine (DAT) are the antimetabolites of thiamine. The aim of study was to compare the effects of OT and DAT pyrophosphates (-PP) on the kinetics of mammalian pyruvate dehydrogenase complex (PDHC) and the in?vitro culture of HeLa cells. The kinetic study showed that 3-deazathiamine pyrophosphate (DATPP) was a much stronger competitive inhibitor (Ki = 0.0026 μM) of PDHC than OTPP (Ki = 0.025 μM). Both Ki values were much lower versus K m for thiamine pyrophosphate (0.06 μM). However, DATPP added to the culture medium for the HeLa cells culture did not hamper the rate of cell growth and showed not significant impact on the viability of the cells, whereas OTPP and OT showed a significant cytostatic effect. The differences between the thiamine antivitamins in their effect on cell growth in?vitro may be due to differences in physicochemical properties and difficulty in DAT transport across the cell membrane.
- Grabowska, Ewa,Czerniecka, Magdalena,Czy?ewska, Urszula,Zambrzycka, Aneta,?otowski, Zenon,Tylicki, Adam
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- Fully continuous flow preparation method of 3-chloro-4-amyl oxoacetate
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The invention belongs to the technical field of organic chemical engineering, and particularly relates to a fully continuous flow preparation method of 3-chloro-4-amyl oxoacetate. The method comprises the following steps of simultaneously conveying chlorine and a reaction solution of acetyl butyrolactone into a micro-channel reactor, and carrying out continuous chlorination reaction to obtain alpha-acetyl-alpha-chloro-gamma-butyrolactone, then continuously conveying the reaction liquid and a mixed solution of glacial acetic acid, hydrochloric acid and water to a micro-reaction system consisting of a next micro-mixer and a micro-channel reactor at the same time, and carrying out continuous acylation reaction to obtain 3-chloro-4-amyl oxoacetate finally, acquiring a final product in a micro-channel system of continuous quenching and continuous extraction separation. Compared with a traditional intermittent kettle type synthesis method, the method disclosed by the invention is short in reaction time, high in product yield, high in automation degree, high in process continuous efficiency, high in space-time yield, low in energy consumption and easy to industrially amplify and apply.
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Paragraph 0005; 0037-0052
(2021/06/22)
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- Synthetic method of thiazoles (by machine translation)
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4 - Acetoxy 3 - acetyl -3 - chloropropyl acetate is hydrolyzed under acidic conditions to prepare 4 -mercapto -2 - methyl -2 - (β - acetoxyethyl)-thiazole; the step of preparing -2 - methyl -2 - (β - acetoxyethyl)-thiazole with 3 - methyl -3 - (β - acetoxyethyl)-thiazole under acidic condition is carried out under an acidic condition by adding an oxidizing agent under an acidic condition in 3 -chloro -3 -methyl 2 - (β - acetoxyethyl)-thiazole in an acidic condition under an acidic condition by adding 4 - an oxidizing agent under an acidic condition; and a -5 - method -5 - for synthesizing thiazoles -4 - and -5 -mercapto 2 -methyl-ethyl)-thiazole in an acidic condition by adding an -5 - oxidizing agent under an -5 - 4 - acidic condition; and the method comprises the following steps: preparing -4 -4 - ethyl acetoxyethyl)-thiazole. The synthesis method is mild in overall reaction condition, simple in post-treatment and suitable for pilot scale test and industrial production. (by machine translation)
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Paragraph 0016-0017; 0021-0022; 0026-0027
(2020/09/16)
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- A PROCESS FOR PREPARING AN INTERMEDIATE OF VITAMIN B1
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The invention provides a new process for preparing o-acyl haloketone, comprising reacting α-halo-α-acyl-butyrolactone with an organic acid in the presence of an acid catalyst and an organic solvent.
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Paragraph 0030; 0031
(2015/11/11)
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- Synthesis of [thiazolium-2,2′-14C2]-SAR97276A from [14C]-thiourea
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[thiazolium-2,2′-14C2]-SAR97276A, a bis(thiazolium) antimalarial development candidate, was synthesized from [ 14C]-thiourea with an overall radiochemical yield of 15%. The synthetic route involves a modified procedure for the synthesis of [ 14C]-sulfurol, also a key intermediate in thiamine synthesis, which was developed due to unlabelled chemistry proving irreproducible with the radiolabelled substrate. Copyright
- Herbert, John M.,Le Strat, Franck,Oumeddour, Delphine G.,Passey, Stephen C.,Taylor, Keith,Whitehead, David M.
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experimental part
p. 89 - 92
(2011/10/02)
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- Synthesis, in vitro and in vivo activity of thiamine antagonist transketolase inhibitors
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Tumor cells extensively utilize the pentose phosphate pathway for the synthesis of ribose. Transketolase is a key enzyme in this pathway and has been suggested as a target for inhibition in the treatment of cancer. In a pharmacodynamic study, nude mice with xenografted HCT-116 tumors were dosed with 1 ('N3′-pyridyl thiamine'; 3-(6-methyl-2-amino-pyridin-3-ylmethyl)-5-(2-hydroxy-ethyl)-4-methyl-thiazol-3-ium chloride hydrochloride), an analog of thiamine, the co-factor of transketolase. Transketolase activity was almost completely suppressed in blood, spleen, and tumor cells, but there was little effect on the activity of the other thiamine-utilizing enzymes α-ketoglutarate dehydrogenase or glucose-6-phosphate dehydrogenase. Synthesis and SAR of transketolase inhibitors is described.
- Thomas, Allen A.,Le Huerou,De Meese,Gunawardana, Indrani,Kaplan, Tomas,Romoff, Todd T.,Gonzales, Stephen S.,Condroski, Kevin,Boyd, Steven A.,Ballard, Josh,Bernat, Bryan,DeWolf, Walter,Han, May,Lee, Patrice,Lemieux, Christine,Pedersen, Robin,Pheneger, Jed,Poch, Greg,Smith, Darin,Sullivan, Francis,Weiler, Solly,Wright, S. Kirk,Lin, Jie,Brandhuber, Barb,Vigers, Guy
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p. 2206 - 2210
(2008/12/20)
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- Synthesis of 3-deazathiamine
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An efficient ten-step synthesis of deazathiamine is described. The synthesis starts from commercially available α-acetyl-γ-butyrolactone and proceeds via deamination of the key aminothiophene 6. The Gewald synthesis of thiophenes is shown to give a mixture of isomeric products with the unsymmetric ketone used here and so a modified procedure giving a single isomer is developed.
- Hawksley, Daniel,Griffin, David A.,Leeper, Finian J.
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p. 144 - 148
(2007/10/03)
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