title: How many enzyme molecules are needed for discrimination oriented applications?
abstract: Chemical reactions establish a molecular mechanism for information processing in living organisms. Here we consider a simple enzymatic reaction model that can be used to discriminate parameters characterizing periodic reagent inflow. Numerical simulations based on the kinetic equations show that there exist a range of inflow frequencies and amplitudes in which the time evolution of the system is very sensitive to small changes in the values of these parameters. However, the kinetic equations are derived for the thermodynamic limit, whereas in a real biological medium, like a cell, the number of enzyme molecules is an integer and finite. We use stochastic simulations to estimate discriminator reliability as a function of the number of enzyme molecules involved. For systems with 10 000 molecules the functionality predicted by kinetic equations is confirmed. If the number of molecules is decreased to 100, discrimination becomes unreliable.
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. jgorecki@ichf.edu.pl.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Gorecki
authors.affiliation: Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw, Poland.
authors.forename: Joanna N
authors.initials: JN
authors.lastname: Gorecka
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. jgorecki@ichf.edu.pl and SGGW, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Nowakowski
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyoto 610-0394, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueno
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyoto 610-0394, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshikawa
mesh_terms: D003198:Computer Simulation; D004798:Enzymes; D008954:Models, Biological
chemical_list: D004798:Enzymes