Study of pH- and temperature-induced transitions in F-protein (phosphofructokinase) by spectroscopy and microcalorimetry methods.
The temperature- and pH-induced transitions in F-protein (phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11] have been studied by means of microcalorimetry and fluorescence and CD spectroscopy. An increase in pH from approx. 6.0 to approx. 8.0 causes a change in the protein state which seems to correspond to a shift of the dimer-tetramer equilibrium in favour of the tetramers. In the absence of phosphate, stability of the protein to temperature- and urea-induced denaturation at pH 6.0 is higher than that at pH 8.0. An addition of 150 mM phosphate results in a pronounced increase in the protein's stability in such a way that the protein becomes more stable at pH 8.0 than at pH 6.0. The shift of the denaturational heat capacity peak induced by the phosphate binding exceeds 25 degrees C at pH 8.0 and 9 degrees C at pH 6.0.
Shnyrov
V L
VL
Institute of Biological Physics, U.S.S.R. Academy of Sciences, Pushchino, Moscow Region.
Freydina
N A
NA
Permyakov
E A
EA
D000818:Animals; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D005453:Fluorescence; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D009132:Muscles / Q000201:enzymology*; D010710:Phosphates / Q000494:pharmacology; D010732:Phosphofructokinase-1; D011188:Potassium / Q000494:pharmacology; D017680:Potassium Compounds; D011489:Protein Denaturation / Q000187:drug effects; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014364:Tryptophan
D046911:Macromolecular Substances; D010710:Phosphates; D017680:Potassium Compounds; D014364:Tryptophan; C013216:potassium phosphate; D010732:Phosphofructokinase-1; D011188:Potassium