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BP: Fachverband Biologische Physik
BP 5: Membranes, Vesicles and Synthetic Life-like Systems I
BP 5.6: Talk
Monday, March 9, 2026, 16:15–16:30, BAR/0205
Theory of Michaelis-Menten kinetics in phase-separated systems — •Gaetano Granatelli1, Samuel S. Gomez1, Sudarshana Laha2, and Christoph A. Weber1 — 1Faculty of Mathematics, Natural Science, and Materials Engineering, Institute of Physics, University of Augsburg, Germany — 2Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
Phase-separated systems can regulate chemical reactions through spatial organization. Motivated by their biological relevance, we develop a mean-field theoretical framework for enzymatic kinetics within liquid condensates formed by phase separation. Building on a model that decouples the phase separation dynamics of scaffold components from the chemical kinetics of dilute clients, we generalize the classical Michaelis-Menten theory of enzyme kinetics to spatially heterogeneous systems with coexisting phases. In our framework, the dynamics of client concentrations are governed by scaffold-controlled parameters such as condensate size, partitioning, relative kinetic coefficients, and diffusion. We explore how they modulate the initial reaction rate across regimes set by the interplay of diffusive and reactive timescales, and we derive explicit expressions for the local reaction rate constants in each phase, allowing direct experimental measurement of how condensates modulate reaction kinetics. We find that, compared to homogeneous conditions, phase-separated liquid condensates can mediate either optimal enhancement or suppression of the initial rate. Our results provide experimentally testable predictions to quantify how phase separation modulates enzymatic activity in living and synthetic systems.
Keywords: Phase separation; Enzyme kinetics; Liquid condensates; Michaelis-Menten theory; Client-scaffold framework