title: Oscillatory isozymes as the simplest model for coupled biochemical oscillators.
abstract: We analyze a simple model for two autocatalytic reactions catalyzed by two distinct isozymes transforming, with different kinetic properties, a given substrate into the same product. This two-variable system can be viewed as the simplest model of chemically coupled biochemical oscillators. Phase-plane analysis indicates how the kinetic differences between the two enzymes give rise to complex oscillatory phenomena such as the coexistence of a stable steady state and a stable limit cycle, or the co-existence of two simultaneously stable oscillatory regimes (birhythmicity). The model allows one to verify a previously proposed conjecture for the origin of birhythmicity. In other conditions, the system admits multiple oscillatory domains as a function of a control parameter whose variation gives rise to markedly different types of oscillations. The latter behavior provides an explanation for the occurrence of multiple modes of oscillations in thalamic neurons.
authors.affiliation: Faculté des Sciences, Université Libre de Bruxelles, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Goldbeter
mesh_terms: D000465:Algorithms; D005246:Feedback; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D008959:Models, Neurological; D009424:Nervous System Physiological Phenomena
chemical_list: D007527:Isoenzymes