کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5507124 | 1537039 | 2017 | 31 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Cytochrome c oxidase inhibition by calcium at physiological ionic composition of the medium: Implications for physiological significance of the effect
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Cytochrome c oxidase (CcO) from mammalian mitochondria binds Ca2+ and Na+ in a special cation binding site. Binding of Ca2+ brings about partial inhibition of the enzyme while Na+ competes with Ca2+ for the binding site and protects the enzyme from the inhibition [Vygodina, T., Kirichenko, A. and Konstantinov, A.A. (2013). Direct Regulation of Cytochrome c oxidase by Calcium Ions. PLoS One 8(9): e74436]. In the original studies, the inhibition was found to depend significantly on the ionic composition of the buffer. Here we describe inhibition of CcO by Ca2+ in media containing the main ionic components of cytoplasm (150 mM KCl, 12 mM NaCl and 1 mM MgCl2). Under these conditions, Ca2+ inhibits CcO with effective Ki of 20-26 μM, that is an order of magnitude higher than determined earlier in the absence of Na+. At physiological value of ionic strength, the inhibition can be observed at any turnover number of CcO, rather than only at low TN (< 10 sâ1) as found previously. The inhibition requires partially oxidized state of cytochrome c and is favored by high ionic strength with a sharp transition at 0.1-0.2 M. The high Ki = 20-26 μM found for CcO inhibition by calcium matches closely the known value of “Km” for Ca2+-induced activation of the mitochondrial calcium uniporter. The inhibition of CcO by Ca2+ is proposed to modulate mitochondrial Ca2+-uptake via the mitochondrial calcium uniporter, promote permeability transition pore opening and induce reduction of Mia40 in the mitochondrial intermembrane space.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1858, Issue 12, December 2017, Pages 982-990
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1858, Issue 12, December 2017, Pages 982-990
نویسندگان
Tatiana V. Vygodina, Elizaveta Mukhaleva, Natalia V. Azarkina, Alexander A. Konstantinov,