[Mechanism for regulating the activity of muscle glycogen phosphorylase b by adenosine-5'-monophosphate].
The kinetics of glycogen chains growth catalyzed by glycogen phosphorylase b from rabbit skeletal muscles at saturating glycogen concentrations have been studied. The applicability of twelve different variants of the Monod-Wyman-Changeux model and six kinetic schemes assuming the interaction of AMP- and glucose 1-phosphate binding sites in the dimeric enzyme molecule is discussed. The kinetic model of the reaction is proposed which suggests: (1) independent binding of AMP and a molecule of glucose 1-phosphate to the dimeric enzyme molecule saturated by glycogen; (2) exclusive binding of the second glucose 1-phosphate molecule by the dimeric enzyme molecule containing two molecules of bound AMP and one molecule of bound glucose 1-phosphate; (3) exclusive ability of the enzyme complex with glycogen, two molecules of AMP and two molecules of glucose 1-phosphate in catalytic transformation. The parameters of the rate equation were calculated by nonlinear regression analysis. The proposed kinetic scheme satisfies the following criteria: (1) convergence in the regressional analysis; (2) reliability of the parameter values; (3) the minimal sum of the weighed squares of residuals. This model was found to fit adequately the kinetics of muscle phosphorylase b reaction at saturating glycogen concentrations.
Klinov
S V
SV
Kurganov
B I
BI
D000249:Adenosine Monophosphate / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D005958:Glucosephosphates / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D007700:Kinetics; D008962:Models, Theoretical; D009132:Muscles / Q000201:enzymology*; D010763:Phosphorylase b / Q000378:metabolism*; D011817:Rabbits
D005958:Glucosephosphates; D000249:Adenosine Monophosphate; D006003:Glycogen; C031590:glucose-1-phosphate; D010763:Phosphorylase b
Mekhanizm reguliatsii aktivnosti myshechnoĭ glikogenfosforilazy b adenozin-5'-monofosfatom.