- Synthesis and characterization of catalytically active thiazolium gold(i)-carbenes
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Thiamin analogs were used to synthesize mono gold(i)-carbene derivatives in a single step under aqueous conditions. The resulting thiazolium gold(i)-carbenes catalyze 5-endo-dig carbocyclization of an acetylenic dicarbonyl compound in organic solvents and hydroalkoxylation of an allene in aqueous buffer.
- Dince, Clément C.,Meoded, Roy A.,Hilvert, Donald
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- Product inhibition of mammalian thiamine pyrophosphokinase is an important mechanism for maintaining thiamine diphosphate homeostasis
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Background: Thiamine diphosphate (ThDP), an indispensable cofactor for oxidative energy metabolism, is synthesized through the reaction thiamine + ATP ? ThDP + AMP, catalyzed by thiamine pyrophosphokinase 1 (TPK1), a cytosolic dimeric enzyme. It was claimed that the equilibrium of the reaction is in favor of the formation of thiamine and ATP, at odds with thermodynamic calculations. Here we show that this discrepancy is due to feedback inhibition by the product ThDP. Methods: We used a purified recombinant mouse TPK1 to study reaction kinetics in the forward (physiological) and for the first time also in the reverse direction. Results: Keq values reported previously are strongly underestimated, due to the fact the reaction in the forward direction rapidly slows down and reaches a pseudo-equilibrium as ThDP accumulates. We found that ThDP is a potent non-competitive inhibitor (Ki ≈ 0.4 μM) of the forward reaction. In the reverse direction, a true equilibrium is reached with a Keq of about 2 × 10?5, strongly in favor of ThDP formation. In the reverse direction, we found a very low Km for ThDP (0.05 μM), in agreement with a tight binding of ThDP to the enzyme. General significance: Inhibition of TPK1 by ThDP explains why intracellular ThDP levels remain low after administration of even very high doses of thiamine. Understanding the consequences of this feedback inhibition is essential for developing reliable methods for measuring TPK activity in tissue extracts and for optimizing the therapeutic use of thiamine and its prodrugs with higher bioavailability under pathological conditions.
- Sambon, Margaux,Pavlova, Oleksandra,Alhama-Riba, Judit,Wins, Pierre,Brans, Alain,Bettendorff, Lucien
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- Preparation method of co-carboxylase and tetrahydrate or salt thereof
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The invention discloses a preparation method of co-carboxylase and tetrahydrate or salt thereof. The invention provides a preparation method of a co-carboxylase shown as a formula I. The method comprises the following steps: eluting a mixture containing the co-carboxylase as shown in the formula I by using weakly-alkaline anion exchange resin through water and a weakly-alkaline aqueous solution with the pH value of 10-12 as eluent in sequence, and collecting eluate to obtain an aqueous solution containing the co-carboxylase as shown in the formula I, wherein the mixture containing the co-carboxylase as shown in the formula I comprises thiamine monophosphate and the co-carboxylase as shown in the formula I.
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Paragraph 0043; 0049-0052; 0056-0058; 0062-0075
(2021/09/21)
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- A PROCESS FOR THE PREPARATION OF A THIAMINE DERIVATIVE AND SALT THEREOF
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A process for the preparation of a thiamine derivative and salt thereof, the process comprising the steps of: reacting thiamine chloride hydrochloride with phosphoric acid in the presence of a catalyst to produce a reaction mass of thiamine polyphosphates; isolating said thiamine derivative from said reaction mass of thiamine polyphosphates; and preparing salt of said thiamine derivative.
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Page/Page column 7
(2016/06/20)
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- Use of vitamin b1 as agents for controlling plant diseases
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The present invention relates to an agent for controlling plant diseases containing vitamin B1, or salts or derivatives thereof as an active ingredient, which exhibits excellent disease controlling effects by rapid induction of defense-related genes in plants infected with pathogens.
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- Method for treating fibrotic diseases or other indications IC
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Provided, among other things, is a method of treating or ameliorating or preventing an indication of the invention in an animal, including a human comprising administering an effective amount of a compound of the formula I:
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- Process for producing 1,4-dihydroxy-2-arylnaphthoate
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Pure 1,4-dihydroxy-2-arylnaphthoate is prepared in high yield by allowing 1,4-dihydroxy-2-naphthoic acid to react with triarylphosphite in the presence of an acid catalyst selected from organic and inorganic acids and crystallizing from a mixed solvent consisting essentially of lower alcohols and water until 1,4-dihydroxy-2-naphthoic acid is isolated and is further purified by crystallization from a mixed solvent consisting essentially of lower alcohols, water and extraction solvent, i.e., alkyl-substituted aromatic hydrocarbons or halogen-substituted aliphatic or aromatic hydrocarbons.
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- Preparation process of acetic acid
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This invention relates to a process for preparing acetic acid from carbon noxide gas and hydrogen gas, which process comprises catalytically reacting carbon monoxide gas and hydrogen gas under elevated pressures and in a liquid medium containing a ruthenium compound, cobalt compound and promoter(s).
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- Process for preparing tertiary phosphines
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Tertiary phosphine oxides, such as triphenylphosphine oxide, are reduced to the corresponding phosphines in the presence of a trialkylaluminum/boron trihalide reducing agent.
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