How many enzyme molecules are needed for discrimination oriented applications?

Area of Science:

• Biochemistry
• Systems Biology
• Chemical Kinetics

Background:

• Living organisms utilize chemical reactions for molecular information processing.
• Enzymatic reactions are fundamental to biological information processing.
• Periodic reagent inflow is a common factor in biological systems.

Purpose of the Study:

• To investigate the reliability of an enzymatic reaction model for discriminating periodic reagent inflow parameters.
• To assess the impact of finite enzyme numbers on information processing reliability.
• To compare predictions from kinetic equations with stochastic simulations in a biological context.

Main Methods:

• Numerical simulations using kinetic equations.
• Stochastic simulations to account for finite molecular numbers.
• Analysis of system sensitivity to parameters like inflow frequency and amplitude.

Main Results:

• Kinetic equations predict reliable parameter discrimination within specific inflow frequency and amplitude ranges.
• Stochastic simulations confirm kinetic predictions for systems with a large number of enzyme molecules (e.g., 10,000).
• Discrimination reliability significantly decreases with a reduced number of enzyme molecules (e.g., 100).

Conclusions:

• The thermodynamic limit assumed in kinetic equations may not hold for biological systems with finite enzyme counts.
• Stochastic effects become significant in biological information processing when molecular numbers are low.
• Accurate molecular information processing in cells requires a sufficient number of enzyme molecules to overcome stochastic noise.