MBM Lab SEMINAR - Lack of detailed balance in biochemical networks

20th February 2025 16:00 CET

Speaker

Eugenia Franco, Hausdorff Center for Mathematics, Bonn, Germany

Abstract

A common feature of many biological systems is that they operate in out of equilibrium conditions. As a consequence, many biochemical networks are described by systems of ODEs that do not satisfy the detailed balance property. In the first part of this talk, we study how to determine if a chemical system satisfies the property of detailed balance when the details of the reactions taking place are not known. To this end, we use the formalism of response functions. In this context the response function R_{ij}(t) is the concentration of the substance j at time t>0, after the injection of the substance i at time t=0. We obtain a condition involving only two reciprocal response functions, Rij(t) and Rji(t), that is necessary, but not sufficient for the detailed balance condition to hold in the network. Moreover, we prove that this necessary condition is also sufficient if a topological condition is satisfied by the network, as well as a stability property that guarantees that the chemical rates are not fine-tuned. In the second part of the talk, I will present a stochastic version of the Hopfield-Ninio kinetic proofreading model, describing a mechanism of antigen recognition by the immune system. Interestingly, this model requires lack of detailed balance in order to function, i.e, in order to be able to discriminate between different antigens. In this talk I will explain that, when the parameters of our model satisfy some specific conditions, then the model has a very high specificity (i.e. it is able to discriminate between different antigens with a low error rate). This work has been done in collaboration with J.J.L. Velázquez and B. Kepka

Contact person: Laboratory of Mathematics for Biology And Medicine Research Group (Andrea Pugliese, Cinzia Soresina).

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Aula Seminari - Povo0, Via Sommarive 14, Trento