title: Sulphate activates phosphorylase b by binding to the Ser (P) site.
abstract: The notion, in a recent crystallographic study on the R state phosphorylase b (Barford, D. and Johnson, L.N. (1989) Nature 340, 609-616), that sulphate ions activate the enzyme by interacting within 2 A of the phosphorylatable Ser-14, is directly supported by kinetic studies on phosphorylase b', a proteolytic species which lacks the N-terminal 16 residues. The results show that this form of the enzyme is no longer activated by ammonium sulphate.
authors.affiliation: Biological Research Center, National Hellenic Research Foundation, Athens, Greece.
authors.forename: D D
authors.initials: DD
authors.lastname: Leonidas
authors.forename: N G
authors.initials: NG
authors.lastname: Oikonomakos
authors.forename: A C
authors.initials: AC
authors.lastname: Papageorgiou
mesh_terms: D000249:Adenosine Monophosphate / Q000494:pharmacology; D000495:Allosteric Site; D000645:Ammonium Sulfate / Q000494:pharmacology; D001665:Binding Sites; D004789:Enzyme Activation; D007700:Kinetics; D010763:Phosphorylase b / Q000378:metabolism*; D011487:Protein Conformation; D012694:Serine; D013431:Sulfates / Q000494:pharmacology*
chemical_list: D013431:Sulfates; D000249:Adenosine Monophosphate; D012694:Serine; D010763:Phosphorylase b; D000645:Ammonium Sulfate