کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9573256 1388893 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Stopped-flow studies of guanine binding by calf spleen purine nucleoside phosphorylase
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Stopped-flow studies of guanine binding by calf spleen purine nucleoside phosphorylase
چکیده انگلیسی
The binding of guanine to calf spleen purine nucleoside phosphorylase at 20 °C, in 20 mM Hepes-NaOH buffer, pH 7.0, at several ionic strength between 5 and 150 mM was investigated using a stopped-flow spectrofluorimeter. The kinetic transients registered after mixing a protein solution with ligand solutions of different concentrations were simultaneously fitted by several association reaction models using nonlinear least-squares procedure based on numerical integration of the chemical kinetic equations appropriate for given model. It is concluded that binding of a guanine molecule by each of the binding sites is a two-step process and that symmetrical trimeric calf spleen purine nucleoside phosphorylase represents a system of (identical) interacting binding sites. The interaction is visible through relations between the rate constants and non-additivity of changes in “molar” fluorescence for different forms of PNP-guanine complexes. It is also probable that electrostatic effects in guanine binding are weak, which indicates that it is the neutral form of the ligand which is bound and dissociated by PNP molecule.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biophysical Chemistry - Volume 115, Issue 1, 1 May 2005, Pages 67-76
نویسندگان
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