title: Crystallographic studies on the activity of glycogen phosphorylase b.
abstract: High resolution studies on the crystal structure of glycogen phosphorylase b have identified the catalytic site to which the substrate glucose-1-phosphate binds strongly with some local conformational changes. The site is situated 8 A (phosphate-to-phosphate distance) from pyridoxal phosphate, an essential cofactor of all glycogen phosphorylases. The catalytic site is 33 A from the site in the N-terminal portion of the molecule to which adenine nucleotides bind. In contrast to phosphorylase a (the active form of the enzyme which is phosphorylated at Ser 14), the positions of the first 19 residues of phosphorylase b are not well defined.
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000495:Allosteric Site; D001665:Binding Sites; D005958:Glucosephosphates / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D008958:Models, Molecular; D009132:Muscles / Q000201:enzymology; D006005:Phosphorylases / Q000378:metabolism; D011487:Protein Conformation; D011732:Pyridoxal Phosphate / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D005958:Glucosephosphates; D000249:Adenosine Monophosphate; D011732:Pyridoxal Phosphate; D000255:Adenosine Triphosphate; D006003:Glycogen; D006005:Phosphorylases