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A tentative mechanism of the ternary complex formation between phosphorylase kinase, glycogen phosphorylase b and glycogen
Author(s) -
Andreeva Iraida E.,
Makeeva Valentina F.,
Kurganov Boris I.,
Chebotareva Nataliya A.,
Livanova Nataliya B.
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00125-8
Subject(s) - phosphorylase kinase , glycogen phosphorylase , glycogen , glycogen synthase , biochemistry , chemistry , glycogen branching enzyme
The kinetics of rabbit skeletal muscle phosphorylase kinase interaction with glycogen has been studied. At pH 6.8 the binding of phosphorylase kinase to glycogen proceeds only in the presence of Mg 2+ , whereas at pH 8.2 formation of the complex occurs even in the absence of Mg 2+ . On the other hand, the interaction of phosphorylase kinase with glycogen requires Ca 2+ at both pH values. The initial rate of the complex formation is proportional to the enzyme and glycogen concentrations, suggesting the formation of the complex with stoichiometry 1:1 at the initial step of phosphorylase kinase binding by glycogen. According to the kinetic and sedimentation data, the substrate of the phosphorylase kinase reaction, glycogen phosphorylase b , favors the binding of phosphorylase kinase with glycogen. We suggest a model for the ordered binding of phosphorylase b and phosphorylase kinase to the glycogen particle that explains the increase in the tightness of phosphorylase kinase binding with glycogen in the presence of phosphorylase b .