Kinetic Mechanism of Allosteric Regulation of Muscle Glycogen Phosphorylaseb by Adenosine

The steady-state kinetics of the reaction catalyzed by glycogen phosphorylase b from rabbit skeletal muscles has been studied in a wide range of the concentrations of adenosine 5 ′ -monophosphate in the direction of glycogen synthesis under the conditions of saturation of the enzyme by glycogen. The kinetic model has been proposed to describe the bell-shaped dependence of the initial rate of the enzymatic reaction on the concentration of adenosine 5 ′ -monophosphate. The parameters of the equation for the initial rate of the enzymatic reaction are calculated by the nonlinear regression method. The conformational transitions in the glycogen phosphorylase b molecule compatible with the proposed kinetic mechanism are discussed.