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The input-output relations of a biological system summarize its functional characteristics. Therefore, answering many fundamental questions on biomolecular machines ultimately reduces to understanding their input-output relations. Enzymes, that catalyze biochemical reactions, are among the simplest machines for which both input and output are chemical in nature. Many enzymatic reactions follow the "Michaelis-Menten" relations between input concentrations and output concentration of the molecular species involved in the reaction. We begin with a graph theoretic analysis of the input-output relation of a single enzyme. Input-output response of a graph can be characterized by the steady-state concentrations of the vertices. We present the conditions that must be satisfied by the structure of the graph (network) of states for the validity of the Michaelis-Menten input-output relation. This analysis sets the stage for understanding, at the next level of complexity, the input-output relation of a molecular machine, that is a macromolecular complex, and then at an even broader context of a group of interacting machines. I'll present an overview of our recent results on these input-output relations at multiple scales.

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Debashish Chowdhury, IIT Kanpur
Seminar Room 0.03, ETP
Contact: Joachim Krug