302-84-1Relevant articles and documents
Catalytic mechanism of serine racemase from Dictyostelium discoideum
Ito, Tomokazu,Maekawa, Motoki,Hayashi, Shuhei,Goto, Masaru,Hemmi, Hisashi,Yoshimura, Tohru
, p. 1073 - 1084 (2013)
The eukaryotic serine racemase from Dictyostelium discoideum is a fold-type II pyridoxal 5′-phosphate (PLP)-dependent enzyme that catalyzes racemization and dehydration of both isomers of serine. In the present study, the catalytic mechanism and role of the active site residues of the enzyme were examined by site-directed mutagenesis. Mutation of the PLP-binding lysine (K56) to alanine abolished both serine racemase and dehydrase activities. Incubation of d- and l-serine with the resultant mutant enzyme, K56A, resulted in the accumulation of PLP-serine external aldimine, while less amounts of pyruvate, α-aminoacrylate, antipodal serine and quinonoid intermediate were formed. An alanine mutation of Ser81 (S81) located on the opposite side of K56 against the PLP plane converted the enzyme from serine racemase to l-serine dehydrase; S81A showed no racemase activity and had significantly reduced d-serine dehydrase activity, but it completely retained its l-serine dehydrase activity. Water molecule(s) at the active site of the S81A mutant enzyme probably drove d-serine dehydration by abstracting the α-hydrogen in d-serine. Our data suggest that the abstraction and addition of α-hydrogen to l- and d-serine are conducted by K56 and S81 at the si- and re-sides, respectively, of PLP.
Metal ion dependency of serine racemase from Dictyostelium discoideum
Ito, Tomokazu,Murase, Hirotaka,Maekawa, Motoki,Goto, Masaru,Hayashi, Shuhei,Saito, Hajime,Maki, Masatoshi,Hemmi, Hisashi,Yoshimura, Tohru
, p. 1567 - 1576 (2012)
d-Serine is known to act as an endogenous co-Agonist of the N-methyl-d-Aspartate receptor in the mammalian brain and is endogenously synthesized from l-serine by Apyridoxal 5′-phosphate-dependent enzyme, serine racemase. Though the soil-living mycetozoa Dictyostelium discoideum possesses no genes homologous to that of NMDA receptor, it contains genes encoding putative proteins relating to the d-serine metabolism, such as serine racemase, d-Amino acid oxidase, and d-serine dehydratase. D. discoideum is an attractive target for the elucidation of the unknown functions of d-serine such as Arole in cell development. As part of the elucidation of the role of d-serine in D. discoideum, we cloned, overexpressed, and examined the properties of the putative serine racemase exhibiting 46% amino acid sequence similarity with the human enzyme. The enzyme is unique in its stimulation by monovalent cations such as Na+ in addition to Mg2+ and Ca2+, which are well-known activators for the mammalian serine racemase. Mg2+ or Na+ binding caused two- to ninefold enhancement of the rates of both racemization and dehydration. The half-maximal activation concentrations of Mg2+ and Na+ were determined to be 1.2 μM and 2.2 mM, respectively. In the l-serine dehydrase reaction, Mg2+ and Na + enhanced the k cat value without changing the K m value. Alanine mutation of the residues E207 and D213, which correspond to the Mg2+-binding site of Schizosaccharomyces pombe serine racemase, abolished the Mg2+- and Na+-dependent stimulation. These results suggest that Mg2+ and Na+ share the common metal ion-binding site.
Direct monitoring of biocatalytic deacetylation of amino acid substrates by1H NMR reveals fine details of substrate specificity
De Cesare, Silvia,McKenna, Catherine A.,Mulholland, Nicholas,Murray, Lorna,Bella, Juraj,Campopiano, Dominic J.
supporting information, p. 4904 - 4909 (2021/06/16)
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.
Preparation and purification method of amino acid compound
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Paragraph 0058; 0059; 0072; 0073; 0074; 0075, (2018/06/21)
The invention relates to the field of industrial organic synthesis, in particular to a preparation and purification method of an amino acid compound. The method comprises the following steps that (1)alpha-amino nitrile compounds or hydantoin compounds or mixtures thereof are heated to react to obtain alpha-amino acid salt under the condition that volatile alkali and a suitable solvent exist; (2)after the alpha-amino acid salt obtained in step (1) is distilled, the alpha-amino acid salt is recrystallized in an organic solvent to obtain the alpha-amino acid compound. According to the method, reaction conditions are mild, materials can be recycled, and introduction of metal ions and use of ammonium carbonate salt are avoided, so that post-treatment is simple and no waste salt is generated.
Degradation of complexons derived from succinic acid under UV radiation
Smirnova,Khizhnyak,Nikol’skii,Khalyapina, Ya. M.,Pakhomov
, p. 507 - 511 (2017/08/02)
The destruction of complexons derived from succinic acid under the action of UV radiation was studied. IR spectroscopy, thin-layer paper chromatography, and complexometric titration were used to determine the destruction products of these complexons. It was found that the complexons decompose under UV irradiation substantially more easily than ethylenediaminetetraacetic acid does, and the products of their decomposition can undergo a biological utilization under natural conditions. The data obtained in the study make it possible to choose, instead of ethylenediaminetetraacetic acid, ligands that will be nearly fully destructible in the light without deteriorating the ecology.