15106-57-7Relevant articles and documents
Synthesis of deuterium labelled L- and D-glutamate semialdehydes and their evaluation as substrates for carboxymethylproline synthase (CarB) - Implications for carbapenem biosynthesis
Sorensen, John L.,Sleeman, Mark C.,Schofield, Christopher J.
, p. 1155 - 1157 (2005)
Carboxymethylproline synthase was shown to condense L-glutamate semialdehyde with malonyl-coenzyme A to produce (2S,5S)-carboxymethylproline, while incubation of D-glutamate semialdehyde results only in uncoupled turnover of malonyl-CoA. The Royal Society of Chemistry 2005.
Identification of 2, 3-dihydrodipicolinate as the product of the dihydrodipicolinate synthase reaction from Escherichia coli
Karsten, William E.,Nimmo, Susan A.,Liu, Jianguo,Chooback, Lilian
, p. 50 - 62 (2018/07/13)
Dihydrodipicolinate synthase (DHDPS) catalyzes the first step in the pathway for the biosynthesis of L-lysine in most bacteria and plants. The substrates for the enzyme are pyruvate and L-aspartate-β-semialdehyde (ASA). The product of the reaction was originally proposed to be 2,3-dihydrodipicolinate (DHDP), but has now generally been assumed to be (4S)-4-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinate (HTPA). ASA is unstable at high pH and it is proposed that ASA reacts with itself. At high pH ASA also reacts with Tris buffer and both reactions are largely reversible at low pH. It is proposed that the basic un-protonated form of the amine of Tris or the α-amine of ASA reacts with the aldehyde functional group of ASA to generate an imine product. Proton NMR spectra of ASA done at different pH values shows new NMR peaks at high pH, but not at low pH, confirming the presence of reaction products for ASA at high pH. The enzymatic product of the DHDPS reaction was examined at low pH by proton NMR starting with either 3 h-pyruvate or 3 d-pyruvate and identical NMR spectra were obtained with four new NMR peaks observed at 1.5, 2.3, 3.9 and 4.1 ppm in both cases. The NMR results were most consistent with DHDP as the reaction product. The UV-spectral studies of the DHDPS reaction shows the formation of an initial product with a broad spectral peak at 254 nM. The DHDPS reaction product was further examined by reduction of the enzymatic reaction components with borohydride followed by GC-MS analysis of the mixture. Three peaks were found at 88, 119 and 169 m/z, consistent with pyruvate, homoserine (reduction product of ASA), and the reduction product of DHDP (1,2,3,6-tetrahydropyridine-2,6-dicarboxylate). There was no indication for a peak associated with the reduced form of HTPA.
Under-flame Reaction of Sulfur-containing Amino Acids by a Hydrogen-Oxygen Flame
Nomoto, Shinya,Shimoyama, Akira,Shiraishi, Susumu,Seno, Tomoyuki,Sahara, Denzo
, p. 643 - 649 (2007/10/03)
Methionine was subjected to a flame-induced reaction in water or in an aqueous formic acid solution by using a hydrogen (50%)-oxygen (50%), hydrogen (87%)-oxygen (13%) and hydrogen diffusion flame. Besides the already-known stepwise oxidation by a hydroxyl radical, the contribution of a hydrogen atom from the flame to the reaction was recognized when the hydrogen-rich mixtures were employed. Homoserine was obtained under all the reaction conditions employed here, and glutamic acid when employing aqueous formic acid as a solvent. A common intermediate, the 3-carboxy-3-aminopropyl radical, appeared to exist in the reaction pathway. A coupling reaction of this radical with a hydrogen atom, hydroxyl radical and hydroxycarbonyl radical afforded 2-aminobutyric acid, homoserine and glutamic acid, respectively. Lanthionine and S-methylcysteine underwent the same reactions. Increasing the hydrogen content of the fuel and adding formic acid to the solvent resulted in retarding the reaction rate. The latter modification of the reaction system also brought about greater stability of the reaction products.
