کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1909513 1046728 2010 4 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Quercetin is a substrate for the transmembrane oxidoreductase Dcytb
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی سالمندی
پیش نمایش صفحه اول مقاله
Quercetin is a substrate for the transmembrane oxidoreductase Dcytb
چکیده انگلیسی

Duodenal cytochrome b (Dcytb) is a transmembrane oxidoreductase protein found in apical membranes of duodenal enterocytes, as well as human erythrocytes, with the capacity to transport electrons donated by cytosolic ascorbate to extracellular electron receptors such as Fe(III), dehydroascorbate, or molecular O2. We have investigated the capacity of the flavonoid quercetin to act as an electron donor for Dcytb in a manner similar to that of ascorbate by observing the reduction of extracellular Fe(III) to Fe(II) in either Madin–Darby canine kidney (MDCK) cells overexpressing Dcytb (Dcytb+) or Dcytb-null MDCK cells. In Dcytb+ cells there is a saturable increase in extracellular Fe(III) reduction in response to increasing intracellular quercetin concentrations (Km = 6.53 ± 1.57 μM), in addition to a small linear response, whereas in Dcytb-null cells there is only a small linear increase in extracellular Fe(III) reduction. No extracellular Fe(III) reduction occurs in Dcytb-null cells when the cells are preloaded with ascorbate. Flavonoids such as quercetin at their physiological concentrations can therefore function as modulators of ferric reductases, enhancing the import of Fe(II) and also providing extracellular reducing potential.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 48, Issue 10, 15 May 2010, Pages 1366–1369
نویسندگان
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