- Cyanide as a primordial reductant enables a protometabolic reductive glyoxylate pathway
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Investigation of prebiotic metabolic pathways is predominantly based on abiotically replicating the reductive citric acid cycle. While attractive from a parsimony point of view, attempts using metal/mineral-mediated reductions have produced complex mixtures with inefficient and uncontrolled reactions. Here we show that cyanide acts as a mild and efficient reducing agent mediating abiotic transformations of tricarboxylic acid intermediates and derivatives. The hydrolysis of the cyanide adducts followed by their decarboxylation enables the reduction of oxaloacetate to malate and of fumarate to succinate, whereas pyruvate and α-ketoglutarate themselves are not reduced. In the presence of glyoxylate, malonate and malononitrile, alternative pathways emerge that bypass the challenging reductive carboxylation steps to produce metabolic intermediates and compounds found in meteorites. These results suggest a simpler prebiotic forerunner of today’s metabolism, involving a reductive glyoxylate pathway without oxaloacetate and α-ketoglutarate—implying that the extant metabolic reductive carboxylation chemistries are an evolutionary invention mediated by complex metalloproteins. [Figure not available: see fulltext.].
- Krishnamurthy, Ramanarayanan,Pulletikurti, Sunil,Yadav, Mahipal,Yerabolu, Jayasudhan R.
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p. 170 - 178
(2022/02/11)
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- Competitive reactions during amine addition to cis-aconityl anhydride
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Amine addition to cis-aconityl anhydride has been used to prepare monomers needed to make water-soluble polymers that are being developed for biomedical applications. Unfortunately competitive decarboxylation, double bond isomerization, and hydrolysis rea
- Dinand, Elisabeth,Zloh, Mire,Brocchini, Steve
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p. 467 - 474
(2007/10/03)
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- Reaction of maleic anhydride with active methylene or methine containing compounds
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Novel polyfunctional compounds and a process for their preparation are disclosed. These compounds and their alkali metal salts are useful metal sequestrants and/or detergent builders. Selected compounds are also intermediates useful in the syntheses of aconitic acid as well as isocitric and alloisocitric acids and their lactones. The novel polyfunctional compounds are obtained from the reaction of maleic anhydride with selected active methylene or methine containing compounds.
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- Preparation of cis and trans aconitic acids and their salts
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Novel polyfunctional compounds and a novel process for their preparation are disclosed. These compounds may be converted into the acid or salt forms of cis and trans aconitic acids as well as into a racemic mixture of isocitric acid, alloisocitric acid and the lactones of isocitric acid and alloisocitric acid and their salts. All of the acid and salt forms produced are useful as metal sequestrants and/or detergent builders. The novel polyfunctional compounds can also be saponified to their corresponding alkali metal salts which, in turn, are also metal ion seqestering agents and detergent builders. The polyfunctional compounds are the reaction products obtained from the reaction of selected salts of monoalkyl esters of maleic acid with selected active hydrogen containing compounds.
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