کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10795653 1052589 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Reaction of wild-type and Glu243Asp variant yeast cytochrome c oxidase with O2
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Reaction of wild-type and Glu243Asp variant yeast cytochrome c oxidase with O2
چکیده انگلیسی
We have studied internal electron transfer during the reaction of Saccharomyces cerevisiae mitochondrial cytochrome c oxidase with dioxygen. Similar absorbance changes were observed with this yeast oxidase as with the previously studied Rhodobacter sphaeroides and bovine mitochondrial oxidases, which suggests that the reaction proceeds along the same trajectory. However, notable differences were observed in rates and electron-transfer equilibrium constants of specific reaction steps, for example the ferryl (F) to oxidized (O) reaction was faster with the yeast (0.4 ms) than with the bovine oxidase (~ 1 ms) and a larger fraction CuA was oxidized with the yeast than with the bovine oxidase in the peroxy (PR) to F reaction. Furthermore, upon replacement of Glu243, located at the end of the so-called D proton pathway, by Asp the PR → F and F → O reactions were slowed by factors of ~ 3 and ~ 10, respectively, and electron transfer from CuA to heme a during the PR → F reaction was not observed. These data indicate that during reduction of dioxygen protons are transferred through the D pathway, via Glu243, to the catalytic site in the yeast mitochondrial oxidase. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1837, Issue 7, July 2014, Pages 1012-1018
نویسندگان
, , , , , ,