Partial characterization and inactivation of membrane-bound phosphofructokinase from Tetrahymena pyriformis.
In Tetrahymena pyriformis, 6-phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) is membrane-bound. Enzyme activity is solubilized by treatment of membranes with Triton X-100 or by high ionic strength in the presence of a chelator. The solubilized enzyme has an approximate molecular weight of 300 000. Both the membrane-bound enzyme and the solubilized enzyme exhibit maximum activity over a wide pH range. At low pH, the membrane-bound form of the enzyme is irreversibly inactivated, whereas the solubilized enzyme is not. The membrane-bound enzyme is inactivated by incubation with Mg2+, ATP, fluoride and a soluble factor that is heat labile, nondialysis, (NH4)2SO4 precipitable and sensitive to trypsin. The solubilized enzyme is not inactivated under similar conditions.
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D005459:Fluorides / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000502:physiology; D008970:Molecular Weight; D017830:Octoxynol; D010732:Phosphofructokinase-1 / Q000032:analysis* / Q000037:antagonists & inhibitors; D011092:Polyethylene Glycols; D011506:Proteins / Q000502:physiology; D013769:Tetrahymena pyriformis / Q000201:enzymology*
D011506:Proteins; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D017830:Octoxynol; D010732:Phosphofructokinase-1; D008274:Magnesium; D005459:Fluorides