کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5507157 1400314 2017 30 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Functional heterogeneity of Fo·F1H+-ATPase/synthase in coupled Paracoccus denitrificans plasma membranes
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Functional heterogeneity of Fo·F1H+-ATPase/synthase in coupled Paracoccus denitrificans plasma membranes
چکیده انگلیسی
Fo·F1H+-ATPase/synthase in coupled plasma membrane vesicles of Paracoccus denitrificans catalyzes ATP hydrolysis and/or ATP synthesis with comparable enzyme turnover. Significant difference in pH-profile of these alternative activities is seen: decreasing pH from 8.0 to 7.0 results in reversible inhibition of hydrolytic activity, whereas ATP synthesis activity is not changed. The inhibition of ATPase activity upon acidification results from neither change in ADP(Mg2 +)-induced deactivation nor the energy-dependent enzyme activation. Vmax, not apparent KmATP is affected by lowering the pH. Venturicidin noncompetitively inhibits ATP synthesis and coupled ATP hydrolysis, showing significant difference in the affinity to its inhibitory site depending on the direction of the catalysis. This difference cannot be attributed to variations of the substrate-enzyme intermediates for steady-state forward and back reactions or to possible equilibrium between ATP hydrolase and ATP synthase Fo·F1 modes of the opposite directions of catalysis. The data are interpreted as to suggest that distinct non-equilibrated molecular isoforms of Fo·F1 ATP synthase and ATP hydrolase exist in coupled energy-transducing membranes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1858, Issue 11, November 2017, Pages 939-944
نویسندگان
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