کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9886118 | 1537496 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Purification and characterization of RihC, a xanthosine-inosine-uridine-adenosine-preferring hydrolase from Salmonella enterica serovar Typhimurium
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Salmonella enterica serovar Typhimurium normally salvage nucleobases and nucleosides by the action of nucleoside phosphorylases and phosphoribosyltransferases. In contrast to Escherichia coli, which catabolizes xanthosine by xanthosine phosphorylase (xapA), Salmonella cannot grow on xanthosine as the sole carbon and energy source. By functional complementation, we have isolated a nucleoside hydrolase (rihC) that can complement a xapA deletion in E. coli and we have overexpressed, purified and characterized this hydrolase. RihC is a heat stable homotetrameric enzyme with a molecular weight of 135 kDa that can hydrolyze xanthosine, inosine, adenosine and uridine with similar catalytic efficiency (kcat/Km=1 to 4Ã104 Mâ1sâ1). Cytidine and guanosine is hydrolyzed with approximately 10-fold lower efficiency (kcat/Km=0.7 to 1.2Ã103 Mâ1sâ1) while RihC is unable to hydrolyze the deoxyribonucleosides thymidine and deoxyinosine. The Km for all nucleosides except adenosine is in the mM range. The pH optimum is different for inosine and xanthosine and the hydrolytic capacity (kcat/Km) is 5-fold higher for xanthosine than for inosine at pH 6.0 while they are similar at pH 7.2, indicating that RihC most likely prefers the neutral form of xanthosine.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1723, Issues 1â3, 25 May 2005, Pages 55-62
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1723, Issues 1â3, 25 May 2005, Pages 55-62
نویسندگان
Michael Riis Hansen, Gert Dandanell,