کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1179608 962785 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Binding studies of hydantoin racemase from Sinorhizobium meliloti by calorimetric and fluorescence analysis
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Binding studies of hydantoin racemase from Sinorhizobium meliloti by calorimetric and fluorescence analysis
چکیده انگلیسی
Hydantoin racemase enzyme together with a stereoselective hydantoinase and a stereospecific d-carbamoylase guarantee the total conversion from d,l-5-monosubstituted hydantoins with a low velocity of racemization, to optically pure d-amino acids. Hydantoin racemase from Sinorhizobium meliloti was expressed in Escherichia coli. Calorimetric and fluorescence experiments were then carried out to obtain the thermodynamic binding parameters, ΔG, ΔH and ΔS for the inhibitors l- and d-5-methylthioethyl-hydantoin. The number of active sites is four per enzyme molecule (one per monomer), and the binding of the inhibitor is entropically and enthalpically favoured under the experimental conditions studied. In order to obtain information about amino acids involved in the active site, four different mutants were developed in which cysteines 76 and 181 were mutated to Alanine and Serine. Their behaviour shows that these cysteines are essential for enzyme activity, but only cysteine 76 affects the binding to these inhibitors.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1764, Issue 2, February 2006, Pages 292-298
نویسندگان
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