A kinetic re-interpretation of the regulation of rabbit skeletal-muscle phosphorylase kinase activity by Ca2+ and phosphorylation
- 1 May 1992
- journal article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 283 (3) , 845-848
- https://doi.org/10.1042/bj2830845
Abstract
The regulation of phosphorylase kinase has been proposed to occur physiologically under conditions of zero-order ultrasensitivity [Meinke & Edstrom (1991) J. Biol. Chem. 266, 2259-2266]. This is also one of the conditions that recent theoretical approaches have indicated to be essential in order for an interconvertible enzyme cascade to generate a sensitive response to an effector [Cardenas & Cornish-Bowden (1989) Biochem. J. 257, 339-345]. In contrast, all published kinetic data to date have strongly suggested that activation of phosphorylase kinase by Ca2+ or phosphorylation is attributable solely to a change in affinity for phosphorylase, with no effect on the Vmax. of the reaction. In this study an attempt is made to resolve this conflict. Findings suggest that changes in Vmax. can fully account for the activation of phosphorylase kinase by the physiological mechanisms of cyclic AMP-dependent phosphorylation and increase in Ca2+ concentration.Keywords
This publication has 24 references indexed in Scilit:
- Muscle glycogenolysis. Regulation of the cyclic interconversion of phosphorylase a and phosphorylase bJournal of Biological Chemistry, 1991
- Characteristics necessary for an interconvertible enzyme cascade to generate a highly sensitive response to an effectorBiochemical Journal, 1989
- THE INTERRELATIONSHIP BETWEEN CAMP-DEPENDENT ALPHA-SUBUNIT AND BETA-SUBUNIT PHOSPHORYLATION IN THE REGULATION OF PHOSPHORYLASE-KINASE ACTIVITY - STUDIES USING SUBUNIT SPECIFIC PHOSPHATASES1987
- Subunit phosphorylation and activation of phosphorylase kinase in perfused rat hearts.Journal of Biological Chemistry, 1987
- CYTOCHEMICAL IDENTIFICATION OF THE REGULATORY SUBUNIT OF THE CAMP-DEPENDENT PROTEIN-KINASE BY USE OF FLUORESCENTLY LABELED CATALYTIC SUBUNIT - EXAMINATION OF PROTEIN-KINASE DISSOCIATION IN HEPATOMA-CELLS RESPONDING TO 8-BR-CAMP STIMULATION1986
- SUBUNIT PHOSPHORYLATION AND ACTIVATION OF SKELETAL-MUSCLE PHOSPHORYLASE-KINASE BY THE CAMP-DEPENDENT PROTEIN-KINASE - DIVALENT METAL-ION, ATP, AND PROTEIN-CONCENTRATION DEPENDENCE1985
- Chemical and Regulatory Properties of Phosphorylase Kinase and Cyclic Amp‐Dependent Protein KinasePublished by Wiley ,1979
- Interconvertible Enzyme Cascades in Metabolic RegulationCurrent Topics in Cellular Regulation, 1978
- Superiority of interconvertible enzyme cascades in metabolic regulation: Analysis of multicyclic systemsProceedings of the National Academy of Sciences, 1977
- Purification and Properties of Rabbit Skeletal Muscle Phosphorylase b Kinase*Biochemistry, 1964