کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10752079 | 1050322 | 2015 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
'Super-perfect' enzymes: Structural stabilities and activities of recombinant triose phosphate isomerases from Pyrococcus furiosus and Thermococcus onnurineus produced in Escherichia coli
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Triose phosphate isomerases (TIMs) are considered to be 'kinetically perfect' enzymes, limited in their activity only by the rates of diffusion of substrate and product molecules. Most studies conducted thus far have been on mesophile-derived TIMs. Here, we report studies of two extremophile-derived TIMs produced in Escherichia coli: (i) TonTIM, sourced from the genome of the thermophile archaeon, Thermococcus onnurineus, and (ii) PfuTIM, sourced from the genome of the hyperthermophile archaeon, Pyrococcus furiosus (PfuTIM). Although these enzymes are presumed to have evolved to function optimally at temperatures close to the boiling point of water, we find that TonTIM and PfuTIM display second-order rate-constants of activity (kcat/Km values) comparable to mesophile-derived TIMs, at 25 °C. At 90 °C, TonTIM and PfuTIM reach maximum velocities of reaction of â¼106-107 μmol/s/mg, and display kcat/Km values in the range of â¼1010-1011 Mâ1 sâ1, which are three orders of magnitude higher than those reported for mesophile TIMs. Further, the two enzymes display no signs of having undergone any structural unfolding at 90 °C. Such enzymes could thus probably be called 'super-perfect' enzymes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 460, Issue 3, 8 May 2015, Pages 753-758
Journal: Biochemical and Biophysical Research Communications - Volume 460, Issue 3, 8 May 2015, Pages 753-758
نویسندگان
Prerna Sharma, Purnananda Guptasarma,