کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1948263 1054682 2009 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Catalytic mechanisms and specificities of glutathione peroxidases: Variations of a basic scheme
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Catalytic mechanisms and specificities of glutathione peroxidases: Variations of a basic scheme
چکیده انگلیسی

Kinetics and molecular mechanisms of GPx-type enzymes are reviewed with emphasis on structural features relevant to efficiency and specificity. In Sec-GPxs the reaction takes place at a single redox centre with selenocysteine as redox-active residue (peroxidatic Sec, UP). In contrast, most of the non-vertebrate GPx have the UP replaced by a cysteine (peroxidatic Cys, CP) and work with a second redox centre that contains a resolving cysteine (CR). While the former type of enzymes is more or less specific for GSH, the latter are reduced by “redoxins”. The common denominator of the GPx family is the first redox centre comprising the (seleno)cysteine, tryptophan, asparagine and glutamine. In this architectural context the rate of hydroperoxide reduction by UP or CP, respectively, is enhanced by several orders of magnitude compared to that of free selenolate or thiolate. Mammalian GPx-1 dominates H2O2 metabolism, whereas the domain of GPx-4 is the reduction of lipid hydroperoxides with important consequences such as counteracting 12/15-lipoxygenase-induced apoptosis and regulation of inflammatory responses. Beyond, the degenerate GSH specificity of GPx-4 allows selenylation and oxidation to disulfides of protein thiols. Heterodimer formation of yeast GPx with a transcription factor is discussed as paradigm of a redox sensing that might also be valid in vertebrates.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1790, Issue 11, November 2009, Pages 1486–1500
نویسندگان
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