کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1926311 1536453 2009 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Microsomal glutathione transferase 1 exhibits one-third-of-the-sites-reactivity towards glutathione
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Microsomal glutathione transferase 1 exhibits one-third-of-the-sites-reactivity towards glutathione
چکیده انگلیسی

The trimeric membrane protein microsomal glutathione transferase 1 (MGST1) possesses glutathione transferase and peroxidase activity. Previous data indicated one active site/trimer whereas structural data suggests three GSH-binding sites. Here we have determined ligand interactions of MGST1 by several techniques. Nanoelectrospray mass spectrometry of native MGST1 revealed binding of three GSH molecules/trimer and equilibrium dialysis showed three product molecules/trimer (Kd = 320 ± 50 μM). All three product molecules could be competed out with GSH. Reinvestigation of GSH-binding showed one high affinity site per trimer, consistent with earlier data. Using single turnover stopped flow kinetic measurements, Kd could be determined for a low affinity GSH-binding site (2.5 ± 0.5 mM). Thus we can reconcile previous observations and show here that MGST1 contains three active sites with different affinities for GSH and that only the high affinity site is catalytically competent.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 487, Issue 1, 1 July 2009, Pages 42–48
نویسندگان
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