title: Phosphofructokinase from Fasciola hepatica: sequence of the cAMP-dependent protein kinase phosphorylation site.
abstract: We have reported previously that phosphofructokinase from the liver fluke Fasciola hepatica is activated by phosphorylation with cAMP-dependent protein kinase, and that this event appears to be important in vivo for regulation of PFK (E. S. Kamemoto, L. Lan, and T. E. Mansour (1989) Arch. Biochem. Biophys. 271, 553-559). Here, we report the amino acid sequence of the single tryptic phosphopeptide generated after phosphorylation of the purified enzyme with cAMP-dependent protein kinase and [gamma 32P]ATP. Through a combination of Edman microsequence analysis, fast atom bombardment mass spectroscopy, and phosphoamino acid analysis, the sequence of the phosphorylated peptide was determined to be: R-S-T(P)-M-M-I-P-G-M-E-G-K. This sequence is not homologous to any previously determined phosphofructokinase phosphopeptides. Regulatory differences between the mammalian and parasite enzymes are discussed with particular emphasis on regulation by protein phosphorylation.
authors.affiliation: Department of Pharmacology, Stanford University School of Medicine, California 94305.
authors.forename: A M
authors.initials: AM
authors.lastname: Mahrenholz
authors.forename: S A
authors.initials: SA
authors.lastname: Hefta
authors.forename: T E
authors.initials: TE
authors.lastname: Mansour
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005210:Fasciola hepatica / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D010732:Phosphofructokinase-1 / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013379:Substrate Specificity; D014357:Trypsin
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D011494:Protein Kinases; D010732:Phosphofructokinase-1; D014357:Trypsin