title: Base-catalyzed reactivation of glycogen phosphorylase reconstituted with a coenzyme-substrate conjugate and its analogues.
abstract: Glycogen phosphorylase reconstituted with pyridoxal (5')diphospho(1)-alpha-D-glucose (PLDP-Glc) is catalytically inactive but slowly converted to the active enzyme through the cleavage of the pyrophosphate linkage. A similar reaction occurs more rapidly on PLDP-Gal and -Xyl but not on PLDP-Man. Values of pKa for all the reactions are about 8.3, suggesting the participation of a common basic residue in these reactions. Based on the present and other results, it is presumed that Tyr-573 or Lys-574 acts as the base abstracting the proton from 2-hydroxyl group of the glucosyl moiety of PLDP-Glc.
authors: Institute of Scientific and Industrial Research, Osaka University, Japan.
authors: N
authors: N
authors: Horinishi
authors: M
authors: M
authors: Tagaya
authors: T
authors: T
authors: Fukui
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D006005:Phosphorylases / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D011817:Rabbits; D013329:Structure-Activity Relationship
chemical_list: D011732:Pyridoxal Phosphate; C032401:pyridoxal(5')diphospho(1)-glucose; D006005:Phosphorylases