title: [Kinetics of action of phosphorylase kinase in an enzymatic cascade system. II. Assessment of the initial rate of the enzymatic reaction catalyzed by phosphorylase kinase].
abstract: The turbidimetric method for determining the phosphorylase kinase activity has been developed. The reaction mixture contained, alongside with other components of the kinase reaction, also the substrates of glycogen phosphorylase a, the final product of the kinase reaction-glycogen and glucose 1-phosphate (or inorganic phosphate). The kinetics of the cascade enzymatic system were followed by the increment (decrement) of absorbance of the glycogen solution at 360 nm (delta A). The initial rate of the phosphorylase kinase-catalyzed enzymatic reaction, nu 0, can be calculated according to the formula: nu 0 = 2tg alpha/a2, where tg alpha is the initial slope of the kinetic curve in the coordinates: delta A-(time)2 and a2 is the specific enzymatic activity of phosphorylase a. The latter was estimated from the initial rates of the phosphorylase reaction measured by the addition of glycogen to the reaction mixture after the completion of the kinase reaction. The reliability of the turbidimetric method for determining the phosphorylase kinase activity was proved by comparison with a direct method based on the measurement of the amount of incorporated 32P.
authors.forename: V F
authors.initials: VF
authors.lastname: Makeeva
authors.forename: I E
authors.initials: IE
authors.lastname: Andreeva
authors.forename: N B
authors.initials: NB
authors.lastname: Livanova
authors.forename: B I
authors.initials: BI
authors.lastname: Kurganov
mesh_terms: D000818:Animals; D002384:Catalysis; D006003:Glycogen / Q000378:metabolism; D007700:Kinetics; D018482:Muscle, Skeletal / Q000201:enzymology; D010764:Phosphorylase Kinase / Q000378:metabolism*; D011817:Rabbits; D013379:Substrate Specificity
chemical_list: D006003:Glycogen; D010764:Phosphorylase Kinase