In vitro control analysis of an enzyme system: experimental and analytical developments

Area of Science:

• Biochemistry
• Systems Biology
• Metabolic Engineering

Background:

• Reconstituting metabolic pathways from purified enzymes is crucial for understanding cellular processes.
• Developing dynamic systems that mimic cellular environments is essential for accurate metabolic analysis.
• Enzyme kinetics and metabolic control analysis require precise experimental conditions.

Purpose of the Study:

• To develop and validate a flow-through system for reconstituting metabolic reactions using purified enzymes.
• To investigate the achievement of a steady state in a continuous flow system for enzymatic reactions.
• To perform metabolic control analysis on the reconstituted system and verify theoretical principles.

Main Methods:

• A flow-through reaction chamber was designed to continuously supply enzymes and reagents.
• Lactate dehydrogenase was used as a model enzyme due to its spectrophotometrically monitorable NADH consumption.
• Control coefficients for enzyme flux and NADH concentration were measured to assess system dynamics.

Main Results:

• A steady state was successfully achieved in the flow-through system.
• Control coefficients (CLDH and Cpump) were accurately measured, confirming the applicability of the summation theorem.
• The system demonstrated precise control over titrations, leading to reliable coefficient estimations.

Conclusions:

• The developed flow-through system is effective for reconstituting metabolic pathways and achieving steady-state conditions.
• This system facilitates accurate metabolic control analysis, offering precise estimation of control coefficients.
• The technique shows potential for applications such as detecting metabolic channelling between enzymes.