title: Phosphorylated fructose-1,6-bisphosphatase dephosphorylating protein phosphatase from Saccharomyces cerevisiae.
abstract: Phosphorylation of fructose-1,6-bisphosphatase with cyclic AMP-dependent protein kinase from yeast is accompanied by a 50% decrease in the catalytic activity (Pohlig, G. and Holzer, H. (1985) J. Biol. Chem. 260, 13818-13823). Using reactivation of phoshorylated fructose-1,6-bisphosphatase as assay, a protein phosphatase was about 2,000-fold purified to electrophoretic homogeneity from Saccharomyces cerevisiae. Upon incubation with phosphorylated fructose-1,6-bisphosphatase the purified protein phosphatase not only reverses the 50% inactivation caused by phosphorylation, but also the previously observed change in the pH optimum and in the ratio of activity with Mg2+ or Mn2+. The phosphatase is strongly inhibited by heparin and fluoride. L-Carnitine, orthophosphate, pyrophosphate, and succinate inhibit to 50% at concentrations from 1 to 10 mM. The molecular mass of the native phosphatase was found to be 180,000 Da. Sodium dodecyl sulfate-gel electrophoresis suggested four subunits with a molecular mass of 45,000 Da each. Half-maximal activity was observed with 5 mM Mg2+ or Mn2+, the pH optimum of activity was found at pH 7. Using polyclonal antibodies, disappearance of 32P-labeled fructose-1,6-bisphosphatase and concomitant liberation of the expected amount of inorganic [32P] phosphate was demonstrated.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D005459:Fluorides / Q000494:pharmacology; D006597:Fructose-Bisphosphatase / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008970:Molecular Weight; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
chemical_list: D008345:Manganese; D006493:Heparin; D011494:Protein Kinases; D006597:Fructose-Bisphosphatase; D010749:Phosphoprotein Phosphatases; D008274:Magnesium; D005459:Fluorides