[Kinetics of kinase phosphorylase action in a cascade enzymatic system. I. Theoretical basis of a method for determining phosphorylase kinase activity]

Based on a theoretical analysis of functioning of a monocascade enzymatic system, a method for continuous monitoring of the phosphorylase kinase-catalyzed enzymatic reaction has been developed. The method is based on the ability of the kinase reaction product--the phosphorylated form of glycogen phosphorylase (form a)-to catalyze glycogen phosphorolysis (with inorganic phosphate as the low molecular weight substrate) or synthesis (with glucose 1-phosphate) in the absence of AMP. A turbidimetric method may be used for the monitoring of the reaction of glycogen degradation (or synthesis) by phosphorylase a formed in the course of the kinase reaction. A method to calculate the initial rate of the kinase reaction from an absorbance versus (time)2 plot has been theoretically substantiated.