Oscillatory isozymes as the simplest model for coupled biochemical oscillators.
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.
Li
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Y
Faculté des Sciences, Université Libre de Bruxelles, Belgium.
Goldbeter
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A
D000465:Algorithms; D005246:Feedback; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D008959:Models, Neurological; D009424:Nervous System Physiological Phenomena
D007527:Isoenzymes