کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2053291 | 1074270 | 2005 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Role of Cys-295 on subunit interactions and allosteric regulation of phosphofructokinase-2 from Escherichia coli Role of Cys-295 on subunit interactions and allosteric regulation of phosphofructokinase-2 from Escherichia coli](/preview/png/2053291.png)
In a previous work, chemical modification of Cys-238 of Escherichia coli Pfk-2 raised concerns on the importance of the dimeric state of Pfk-2 for enzyme activity, whereas modification of Cys-295 impaired the enzymatic activity and the MgATP-induced tetramerization of the enzyme. The results presented here demonstrate that the dimeric state of Pfk-2 is critical for the stability and the activity of the enzyme. The replacement of Cys-238 by either Ala or Phe shows no effect on the kinetic parameters, allosteric inhibition, dimer stability and oligomeric structure of Pfk-2. However, the mutation of Cys-295 by either Ala or Phe provokes a decrease in the kcat value and an increment in the Km values for both substrates. We suggest that the Cys-295 residue participates in intersubunit interactions in the tetramer since the Cys-295-Phe mutant exhibits higher tetramer stability, which in turn results in an increase in the fructose-6-P concentration required for the reversal of the MgATP inhibition relative to the wild type enzyme.
Journal: FEBS Letters - Volume 579, Issue 11, 25 April 2005, Pages 2313–2318