کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2553058 1124880 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Nucleotide metabolizing ecto-enzymes in Walker 256 tumor cells: Molecular identification, kinetic characterization and biochemical properties
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی کاردیولوژی و پزشکی قلب و عروق
پیش نمایش صفحه اول مقاله
Nucleotide metabolizing ecto-enzymes in Walker 256 tumor cells: Molecular identification, kinetic characterization and biochemical properties
چکیده انگلیسی

In this study we describe the molecular identification, kinetic characterization and biochemical properties of an E-NTPDase and an 5′-nucleotidase in Walker 256 cells. For the ATP, ADP and AMP hydrolysis there were optimum pH in the range 6.5–8.0, and absolute requirement for divalent cations (Mg2+ > Ca2+). A significant inhibition of ATP and ADP hydrolysis was observed in the presence of high concentrations of sodium azide and 0.5 mM of Gadolinium chloride. These activities were insensitive to ATPase, adenylate kinase and alkaline phosphatase classical inhibitors. The Km values were 464.2 ± 86.6 μM (mean ± SEM, n = 4), 137.0 ± 31 μM (mean ± SEM, n = 5) and 44.8 ± 10.2 μM (mean ± SEM, n = 4), and Vmax values were 655.0 ± 94.6 (mean ± SEM, n = 4), 236.3 ± 27.2 (mean ± SEM, n = 5) and 177.6 ± 13.8 (mean ± SEM, n = 5) nmol of inorganic phosphate min− 1 mg of protein− 1 for ATP, ADP and AMP, respectively. Using RT-PCR analysis we identified the mRNA of two members of the ecto-nucleoside triphosphate diphosphohydrolase family (NTPDase 2 and 5) and a 5′-nucleotidase. The presence of NTPDases and 5′-nucleotidase enzymes in Walker 256 tumor cells may be important to regulate the ratio adenine nucleotides/adenine nucleoside extracellularly, therefore motivating tumor growth.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Life Sciences - Volume 80, Issue 10, 13 February 2007, Pages 950–958
نویسندگان
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