cAMP-dependent phosphorylation activates phosphofructokinase from mantle tissue of the mollusc Mytilus galloprovincialis. Identification of the phosphorylated site.
Phosphofructokinase from mantle tissue of the sea mussel Mytilus galloprovincialis was phosphorylated in vitro by a protein kinase isolated from the same tissue, homologous to mammalian cAMP-dependent protein kinase; the maximal level of phosphorylation achieved was around 1 mol of Pi/mol of phosphofructokinase subunit. The covalent incorporation of phosphate leads to a notable increase in the enzyme activity assayed at near-physiological concentrations of substrates and allosteric modulators and neutral pH. Tryptic digestion of labeled phosphofructokinase released a phosphopeptide whose sequence was Lys-Asp-Ser(P)-Ile-Trp-Ile-Gln-Thr-Gly-Arg. This sequence showed high homology with the phosphopeptides from other invertebrates whose phosphofructokinase is also activated by cAMP-dependent phosphorylation.
Fernández
M
M
Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Lugo, Spain.
Cao
J
J
Vega
F V
FV
Hellman
U
U
Wernstedt
C
C
Villamarín
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia / Q000201:enzymology*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010732:Phosphofructokinase-1 / Q000737:chemistry / Q000378:metabolism*; D010748:Phosphopeptides / Q000378:metabolism; D010766:Phosphorylation
D010748:Phosphopeptides; D000242:Cyclic AMP; D010732:Phosphofructokinase-1; D017868:Cyclic AMP-Dependent Protein Kinases