70-54-2Relevant articles and documents
A method for preparing DL-lysine
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Paragraph 0032; 0033, (2017/04/03)
The invention provides a method for preparing DL-lysine with chiral lysine salt as a raw material. The method specifically comprises the following steps: dissolving chiral lysine salt in an acetic acid water solution, adding salicylaldehyde or benzaldehyde as a catalyst, carrying out heating and racemization, removing solvents through vacuum distillation after racemization is completed, washing a residual solid with ethanol, obtaining DL-lysine salt, removing salt with an ion exchange column and carrying out concentration and decoloration, thus obtaining a DL-lysine solid. The preparation method has the advantages that the preparation method is lower in production cost and simple in process; pollution is not easily caused in the production process; the racemization rate of L-lysine hydrochloride can be 100%; the purity of the obtained DL-lysine finished product is more than 98%.
Lysine racemase from a lactic acid bacterium, Oenococcus oeni: Structural basis of substrate specificity
Kato, Shiro,Hemmi, Hisashi,Yoshimura, Tohru
, p. 505 - 508 (2013/02/25)
Oenococcus oeni, a lactic acid bacterium, possesses a lysine racemase, which has a specific activity towards basic amino acids. A comparison of amino acid residues around the active site suggested that Ile222 and Tyr354 of the Geobacillus stearothermophilus alanine racemase, which shares 60% sequence similarity with lysine racemase, were replaced by Thr224 and Trp355 in the O. oeni lysine racemase. T224I/W355Y double mutations significantly decreased the activity of lysine racemase, whereas I222T/Y354W double mutations endowed alanine racemase with lysine racemization activity. These results suggest that the two residues play an important role in lysine racemization.
Kinetics and mechanism of thermal decomposition of kynurenines and biomolecular conjugates: Ramifications for the modification of mammalian eye lens proteins
Kopylova, Lyudmila V.,Snytnikova, Olga A.,Chernyak, Elena I.,Morozov, Sergey V.,Forbes, Malcolm D. E.,Tsentalovich, Yuri P.
experimental part, p. 2958 - 2966 (2011/02/25)
Thermal degradation reactions of kynurenine (KN), 3-hydroxykynurenine (3OHKN), and several adducts of KN, to amino acids and reduced glutathione (GSH) have been studied at physiological temperature. These compounds are all implicated in age-related mammalian eye lens cataract formation at the molecular level. The main reaction pathway for both KN and 3OHKN is deamination viaβ-elimination to carboxyketoalkenes CKA and 3OHCKA. These reactions show a weak pH dependence below pH values of ~8, and a strong pH dependence above this value. The 3OHKN structure deaminates at a faster rate than KN. A mechanism for the deamination reaction is proposed, involving an aryl carbonyl enol/enolate ion, that is strongly supported by the structural, kinetic, and pH data. The degradation of Lys, His, Cys and GSH adducts of the CKA moieties was also studied. The Lys adduct was found to be relatively stable over 200 h at 37 °C, while significant degradation was observed for the other adducts. The results are discussed in terms of known post-translational modification reactions of the lens proteins and compared to incubation studies involving KN and related compounds in the presence of proteins.