کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
674581 1459567 2011 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Kinetic and thermodynamic study of the reaction catalyzed by glucose-6-phosphate dehydrogenase with nicotinamide adenine dinucleotide
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Kinetic and thermodynamic study of the reaction catalyzed by glucose-6-phosphate dehydrogenase with nicotinamide adenine dinucleotide
چکیده انگلیسی

The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) from Leuconostoc mesenteroides has a dual coenzyme specificity with oxidized nicotinamide adenine dinucleotide (NADox) and oxidized nicotinamide adenine dinucleotide phosphate as electron acceptors. The G6PD coenzyme selection is determined by the metabolic cellular prevailing conditions. In this study a kinetic and thermodynamic analysis is presented for the reaction catalyzed by G6PD from L. mesenteroides with NADox as coenzyme in phosphate buffer. For this work, an in situ spectrophotometric technique was employed based on the detection of one product of the reaction. Substrate and coenzyme concentrations as well as temperature and pH effects were evaluated. The apparent equilibrium constant, the Michaelis constant, and the turnover number were determined as a function of each experimental condition. The standard transformed Gibbs energy of reaction was determined from equilibrium constants at different initial conditions. For the product 6-phospho-d-glucono-1,5-lactone, a value of the standard Gibbs energy of formation is proposed, ΔfG° = −1784 ± 5 kJ mol−1.

Research highlights
► The reaction catalyzed by one enzyme of the pentose phosphate pathway was studied.
► A spectrophotometric method is proposed for kinetic and thermodynamic analysis.
► The pH and the temperature influences are reported on physical chemical properties.
► Relative concentrations of substrates are also important in the catalytic process.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 517, Issues 1–2, 20 April 2011, Pages 40–44
نویسندگان
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