[Kinetics of action of phosphorylase kinase in a cascade enzymatic system. III. Hysteretic properties of phosphorylase kinase from skeletal muscles].
The kinetic behaviour of rabbit skeletal muscle phosphorylase kinase at variable concentrations of the enzyme and the substrate (glycogen phosphorylase b) has been studied. The kinetic curves reveal a lag period whose duration decreases with a rise in the phosphorylase kinase concentration (when the reaction is initiated by an addition of the ATP + MgCl2 mixture to the enzyme preincubated with phosphorylase b, CaCl2, glycogen and glucose-1-phosphate or inorganic phosphate). A decrease of the phosphorylase b concentration eliminates the lag period. Under these conditions the specific activity of phosphorylase kinase decreases with a rise in the enzyme concentration. The kinetic behaviour of phosphorylase kinase is interpreted in terms of a model of a linearly associating system, such as M reversible M2 reversible M3 reversible ...Mi, where M is the dexadecameric molecule of phosphorylase kinase. Acceleration of the phosphorylase kinase-catalyzed reaction in the course of the enzymatic process seems to be due to the breakdown of inactive enzyme associates (Mi) caused by phosphorylase b. The short gamma-subunit of phosphorylase kinase devoid of the calmodulin-binding domain does not display any hysteretic properties.
Andreeva
I E
IE
Makeeva
V F
VF
Livanova
N B
NB
Kurganov
B I
BI
D000818:Animals; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018482:Muscle, Skeletal / Q000201:enzymology*; D010764:Phosphorylase Kinase / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits
D010764:Phosphorylase Kinase
Kinetika deĭstviia kinazy fosforilazy v kaskadnoĭ fermentnoĭ sisteme. III. Gisterezisnye svoĭstva kinazy fosforilazy iz skeletnykh myshts.