- Direct monitoring of biocatalytic deacetylation of amino acid substrates by1H NMR reveals fine details of substrate specificity
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Amino acids are key synthetic building blocks that can be prepared in an enantiopure form by biocatalytic methods. We show that thel-selective ornithine deacetylase ArgE catalyses hydrolysis of a wide-range ofN-acyl-amino acid substrates. This activity was revealed by1H NMR spectroscopy that monitored the appearance of the well resolved signal of the acetate product. Furthermore, the assay was used to probe the subtle structural selectivity of the biocatalyst using a substrate that could adopt different rotameric conformations.
- De Cesare, Silvia,McKenna, Catherine A.,Mulholland, Nicholas,Murray, Lorna,Bella, Juraj,Campopiano, Dominic J.
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supporting information
p. 4904 - 4909
(2021/06/16)
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- Reactivity of Selenocystine and Tellurocystine: Structure and Antioxidant Activity of the Derivatives
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l-Selenocystine (5) and l-tellurocystine (6) have been prepared and the reactivity of these amino acids, i.e., oxidation of 5 and 6, has been performed at various pH values. Hydrogen peroxide was used as an oxidant and it was treated with 5 and 6 in excess in acidic and basic media. Compound 5, upon oxidation, afforded SeIV and SeVI products. Selenocysteic acid [HO3SeCH2CH(NH2)COOH] 9, a novel SeVI compound, was isolated and characterised by single-crystal X-ray diffraction studies. In contrast, l-tellurocystine, upon oxidation with H2O2, afforded TeII and TeIV products. Zwitterionic organotellurolate(IV), [TeCl3CH2CH(NH3)COOH] 13, was isolated and characterised by NMR and IR spectroscopy, mass spectrometry and elemental analysis. Compound 13 crystallizes in an orthorhombic space group. l-Tellurocystine, when reduced with NaBH4, produced the desired tellurolate intermediate, which was trapped with bromoacetic acid. Furthermore, l- and d-tellurocysteine derivatives, [(RTeCH2CH(NH2)COOH) R=phenyl, substituted phenyl and naphthyl (24–39)] were synthesised and evaluated for their glutathione peroxidase (GPx)-like activities. The results show that l-tellurocysteine derivatives have higher activity than their D-tellurocysteine analogues. DFT calculations for l-tellurocysteine derivatives provided information about the bond lengths and bond angles. This study reveals that the introduction of naphthyl substituents (35–38) leads to twisted conformation of the amino acid derivatives.
- Satheeshkumar, Kandhan,Raju, Saravanan,Singh, Harkesh B.,Butcher, Ray J.
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supporting information
p. 17513 - 17522
(2018/11/23)
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- Preparation method for L-selenocysteine
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The invention belongs to the field of chemical synthesis, and concretely relates to a synthetic method for L-selenocysteine. The method comprises the following steps: a, chloridizing L-serine hydrochloride to obtain 3-chloro-L-alanine hydrochloride; b, performing seleno-reaction of 3-chloro-L-alanine hydrochloride prepared by step a under alkaline condition to obtain L-selenocystine; and c, performing reduction reaction of L-selenocystine to obtain L-selenocysteine. The method has simple steps, high yield, low cost, and good application prospect.
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Paragraph 0028; 0029
(2016/12/26)
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- D-amino acid oxidase, and method for production of L-amino acid, 2-oxo acid, or cyclic imine
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The present invention relates to novel D-amino acid oxidase isolated and purified from Candida intermedia, a gene encoding the D-amino acid oxidase, a recombinant plasmid containing the gene, and a transformant into which the D-amino acid oxidase gene has been introduced, as well as a production method of D-amino acid oxidase including culturing the transformant. Moreover, the present invention relates to a production method of L-amino acids, 2-oxo acids or cyclic imines, which include reacting racemic amino acids with the D-amino acid oxidase, more preferably, a production method of L-amino acids, which includes reacting racemic amino acid with the D-amino acid oxidase, amino acid dehydrogenase and an enzyme having a coenzyme-regenerating activity. According to the present invention, L-amino acids, 2-oxo acids or cyclic imines can be produced with good efficiency in an industrial scale.
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- Processes for producing β-halogeno-α-amino-carboxylic acids and phenylcysteine derivatives and intermediates thereof
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An industrially advantageous method of producing β-halogeno-α-aminocarboxylic acids is provided. Methods are also provided of producing optically active N-protected-S-phenylcysteines having high optical purity and of intermediates thereof, respectively, in which the above production method is utilized. A method of producing β-halogeno-α-aminocarboxylic acids or salts thereof is disclosed which comprises halogenating the hydroxyl group of a β-hydroxy-α-aminocarboxylic acid (in which the basicity of the amino group in α-position is not masked by the presence of a substituent on said amino group) or a salt thereof with an acid with a halogenating agent. A method of producing optically active N-protected-S-phenylcysteines represented by the general formula (3) or salts thereof is further disclosed which comprises applying the above production method to optically active serine or a salt thereof and then carrying out treatment with an amino-protecting agent and reaction with thiophenol under a basic condition.
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- Versatile Synthesis of Stereospecifically Labelled D-Amino Acids via Labelled Aziridines - Preparation of (2R,3S)-- and (2R,3R)--Serine; (2S,2'S,3S,3'S)-- and (2S,2'S,3R,3'R)--Cystine; and (2S,3S)- and (2S,3R)--β-Chloroalanine
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Stereospecifically β-labelled protected 2-carboxyaziridines 2, with the stereochemistry of a D-amino acid at C-2, have been prepared by a chemicoenzymic synthesis.Preparation of the labelled malates 5, by hydration of fumaric acid using the enzyme fumarase or by amination with aspartase followed by nitrosation, was followed by conversion into the isoserines 3, by a process involving Curtius rearrangement with retention of stereochemistry at the chirally labelled primary centre.Protection and ring closure gave the aziridines 2, which, on ring opening with the appropriate nucleophiles and deprotection, gave stereospecifically labelled samples of D-serine 16, D-cystine 20 and β-chloro-D-alanine 22.
- Axelsson, B. Svante,O'Toole, Kevin J.,Spencer, Philip A.,Young, Douglas W.
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p. 807 - 816
(2007/10/02)
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- Syntheses of optically pure α-amino acids from 3-amino-2-oxetanone salts
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A process for the preparation of optically pure α-amino acids comprising the nucleophilic ring-opening of 3-amino-2-oxetanone salts. N-Protected serine β-lactones are deprotected to form heretofore unknown 3-amino-2-oxetanone and its corresponding salts. In turn these previously unknown 3-amino-2-oxetanone salts may be used in the synthesis of other novel or rare stereochemically-pure free amino acids.
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- Kinetic Resolution of Unnatural and Rarely Occuring Amino Acids: Enantioselective Hydrolysis of N-Acyl Amino Acids Catalyzed by Acylase I
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Acylase I (aminoacylase; N-acylamino-acid amidohydrolase, EC 3.5.1.14, from porcine kidney and the fungus Aspergillus) is broadly applicable enzymatic catalyst for the kinetic resolution of unnatural and rarely occuring α-amino acids.Its enantioselectivity for the hydrolysis of N-acyl L-α-amino acids is nearly absolute, yet it accepts substrates having a wide range of structure and functionality.This paper reports the initial rates of enzyme-catalyzed hydrolysis of over 50 N-acyl amino acids and analogues, the stabilities of the enzymes in aqueous and aqueous/organic solutions, and the effects of different acyl groups and metal ions on the rates of enzymatic hydrolysis.Eleven α-amino and α-methyl α-amino acids were resolved on a 2-29-g scale.Crude L- and D-amino acid products had generally >90percent ee.The utility of resolved amino acids as chiral synthons was illustrated by the preparation of (R)- and (S)-1-butene oxide and the diastereoselective (cis:trans, 7-8:1) iodolactonization of three 2-amino-4-alkenoic acid derivatives.
- Chenault, H. Keith,Dahmer, Juergen,Whitesides, George M.
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p. 6354 - 6364
(2007/10/02)
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- Preparation process of β-chloroalanine
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β-Chloroalanine is prepared by reacting in an aqueous medium an aziridine-2-carboxylate with hydrogen chloride in an amount of 2.0-5.0 moles per mole of the aziridine-2-carboxyalte and causing the thus-formed β-chloroalanine to selectively crystallize out from the liquid reaction mixture. Since the solution recovered after the isolation of the crystallized β-chloroalanine still contains β-chloroalanine and by-produced α-chloro-β-alanine dissolved therein, they may be converted into an aziridine-2-carboxylate by treating them with a base to recirculate it for reuse.
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