462-60-2Relevant articles and documents
Quantitative analysis and functional evaluation of zinc ion in the D-hydantoinase from Pseudomonas putida YZ-26
Zhang, Xueyao,Yuan, Jingming,Niu, Lixi,Liang, Aihua
, p. 71 - 81 (2010)
D-Hydantoinase (HDT) is a metal-dependent enzyme that is widely used in industrial bioconversion to D-amino acids as valuable intermediates in the fields of food, pharmaceutical industry and agriculture. In this report, we prepared apo-HDT (metal-removed HDT) and Zn2+-HDT (Zn 2+-added HDT) in vitro from a recombinant HDT (re-HDT) expressed in E. coli. The Zn2+-HDT and re-HDT contain 2.17 and 0.95 mol Zn 2+ per mol subunit, respectively, and they have comparable enzymatic activities. In contrast, the apo-HDT only retains 0.04 mol Zn2+ per mol subunit with less than 10% activity, compared with the re-HDT. When the apo-HDT was reconstituted with ZnCl2, the enzymatic activity recovery was about 75%. Moreover, the fluorescence intensity, circular dichroism spectra and thermo-stability of the apo-HDT and Zn2+-HDT are quite different from those of the re-HDT. These data suggest that the re-HDT may have two Zn2+-binding sites, one is an intrinsic or tight-binding site (zinc-α) essential for its activity and the other is a vacant or loose-binding site (zinc-β) possibly non-essential for the activity. Springer Science+Business Media.
PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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, (2010/03/02)
The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
The peptide formation mediated by cyanate revisited. N-carboxyanhydrides as accessible intermediates in the decomposition of N-carbamoylamino acids
Danger, Gregoire,Boiteau, Laurent,Cottet, Herve,Pascal, Robert
, p. 7412 - 7413 (2007/10/05)
Similar to many ureas, N-carbamoylamino acids were shown to be hydrolyzed in aqueous solution through elimination mechanisms at close to neutral pH, the nucleophilic attack of water being a minor process. Two competing elimination mechanisms can take place involving either cyanate or isocyanate transient intermediates. Peptide formation was observed and attributed to the latter pathway through the intermediacy of amino acid N-carboxyanhydride (NCA). Eventually, cyanate and its precursors (including urea) unexpectedly behave as amino acid activating agents because of their ability in amino acid carbamoylation. Owing to its ability to generate a background prebiotic production of NCAs on the primitive Earth, this reaction is suggested to have contributed to the origin of life process. Copyright