EVENT DETAILS AND ABSTRACT

Title: Enzyme reactions within cells
Speaker: Dr. Santiago Schnell
Speaker Info: School of Informatics, Indiana University
Brief Description:
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Abstract:

The development of new instrumentation in cell biology and biochemistry has dramatically extended enzymology. Now we can examine enzymes and their reactions in living biochemical pathways. Biochemical reactions occur in an intracellular environment which is highly heterogeneous and disordered. For this reason, mass action was presumed invalid for modeling intracellular reactions. We have found how the rate laws describing intracellular reactions vary as a function of: (a) the geometry and size of the intracellular surface on which the reactions occur, (b) the mobility of the macromolecules responsible for the crowding effects, (c) the initial reactant concentrations and the probability of reaction between two reactant molecules. We demonstrate two results, that: (i) the law of mass action can be valid in vivo conditions, and (ii) reactions following non-ideal kinetics can attain steady-state kinetics. These two results are contrary to the current scientific consensus in enzymology. Our results were gained by computation-intensive Monte Carlo simulations. For practical, day-to-day simulations a simpler method is required. We have devised a mesoscopic method which permits the efficient simulation of reactions occurring in disordered media. This new method has already yielded an unexpected result: we find that the heterogeneities of the intracellular medium could play a role in the self-organisation of reactions in the cytoplasm.