[Effect of ATP, ADP and magnesium ions on the activity of phosphorylase kinase from rabbit skeletal muscles].
The dependence of enzymatic activity of phosphorylase kinase on ATP and magnesium concentrations has been studied. The enzyme activity has been shown to be inhibited by the substrate surplus (Mg-ATP) but free Mg2+ stimulates the enzyme. At saturating concentrations of ATP the activating effect of Mg2+ is maximum at the Mg/ATP ratio of 6-10. The ADP inhibition action is characterized by an incompetitive type towards ATP. The apparent Ki value is equal to 0.2 mM. It is suggested that the specific ADP-binding site spatially removed from the active site has an importance for the phosphorylase kinase activity regulation.
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D009132:Muscles / Q000187:drug effects* / Q000201:enzymology; D010764:Phosphorylase Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D013379:Substrate Specificity / Q000187:drug effects
D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010764:Phosphorylase Kinase; D008274:Magnesium
Vliianie ATF, ADF i ionov magniia na aktivnost' kinazy fosforilazy iz skeletnykh myshts krolika.