کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8290439 | 1536359 | 2013 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Kinetic and mechanistic characterization of the glyceraldehyde 3-phosphate dehydrogenase from Mycobacterium tuberculosis
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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
![عکس صفحه اول مقاله: Kinetic and mechanistic characterization of the glyceraldehyde 3-phosphate dehydrogenase from Mycobacterium tuberculosis Kinetic and mechanistic characterization of the glyceraldehyde 3-phosphate dehydrogenase from Mycobacterium tuberculosis](/preview/png/8290439.png)
چکیده انگلیسی
Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a glycolytic protein responsible for the conversion of glyceraldehyde 3-phosphate (G3P), inorganic phosphate and nicotinamide adenine dinucleotide (NAD+) to 1,3-bisphosphoglycerate (1,3-BPG) and the reduced form of nicotinamide adenine dinucleotide (NADH). Here we report the characterization of GAPDH from Mycobacterium tuberculosis (Mtb). This enzyme exhibits a kinetic mechanism in which first NAD+, then G3P bind to the active site resulting in the formation of a covalently bound thiohemiacetal intermediate. After oxidation of the thiohemiacetal and subsequent nucleotide exchange (NADH off, NAD+ on), the binding of inorganic phosphate and phosphorolysis yields the product 1,3-BPG. Mutagenesis and iodoacetamide (IAM) inactivation studies reveal the conserved C158 to be responsible for nucleophilic catalysis and that the conserved H185 to act as a catalytic base. Primary, solvent and multiple kinetic isotope effects revealed that the first half-reaction is rate limiting and utilizes a step-wise mechanism for thiohemiacetal oxidation via a transient alkoxide to promote hydride transfer and thioester formation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 540, Issues 1â2, December 2013, Pages 53-61
Journal: Archives of Biochemistry and Biophysics - Volume 540, Issues 1â2, December 2013, Pages 53-61
نویسندگان
Brett Wolfson-Stofko, Timin Hadi, John S. Blanchard,