Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50361
標題: Probing the location and function of the conserved histidine residue of phosphoglucose isomerase by using an active site directed inhibitor N-bromoacetylethanolamine phosphate
作者: Meng, M.S.
孟孟孝
Chane, T.L.
Sun, Y.J.
Hsiao, C.D.
關鍵字: Bacillus stearothermophilus
catalytic mechanism
glucose-6-phosphate
isomerase
N-bromoacetylethanolamine phosphate
phosphoglucose
isomerases
site-directed mutagenesis
nonspherocytic hemolytic-anemia
autocrine motility factor
bacillus-stearothermophilus
glucose-6-phosphate isomerase
glucosephosphate isomerase
6-phosphoglucose isomerase
phosphohexose
isomerase
nucleotide-sequence
gpi deficiency
neuroleukin
期刊/報告no:: Protein Science, Volume 8, Issue 11, Page(s) 2438-2443.
摘要: Phosphoglucose isomerase (EC 5.3.1.9) catalyzes the interconversion of D-glucopyranose-6-phosphate and D-fructofuranose-6-phosphate by promoting an intrahydrogen transfer between C1 and C2. A conserved histidine exists throughout all phosphoglucose isomerases and was hypothesized to be the base catalyzing the isomerization reaction. in the present study, this conserved histidine, His311, of the enzyme from Bacillus stearothermophilus was subjected to mutational analysis, and the mutational effect on the inactivation kinetics by N-bromoacetylethanolamine phosphate was investigated. The substitution of His311 with alanine, asparagine, or glutamine resulted in the decrease of activity, in k(cat)/K-M, by a factor of 10(3), indicating the importance of this residue. N-brumoacetylethanolamine phosphate inactivated irreversibly the activity of wild-type phosphoglucose isomerase; however, His311 --> Ala became resistant to this inhibitor, indicating that His311 is located in the active site and is responsible for the inactivation of the enzyme by this active site-directed inhibitor. The pK(a) of His311 was estimated to be 6.31 according to the pH dependence of the inactivation. The proximity of this value with the pK(a) value of 6.35, determined from the pH dependence of k(cat)/K-M, supports a role of His311 as a general base in the catalysis.
URI: http://hdl.handle.net/11455/50361
ISSN: 0961-8368
Appears in Collections:生物科技學研究所

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