Metabolic dynamics restricted by conserved carriers: Jamming and feedback.

Area of Science:

• Systems Biology
• Metabolic Engineering
• Biophysics

Background:

• Understanding cellular physiology requires insight into metabolic dynamics.
• Constraint-based approaches predict metabolic steady states using conserved quantities like ATP/ADP and NADH/NAD+.
• The dynamic impact of these conservation laws on metabolic systems remains incompletely understood.

Purpose of the Study:

• To investigate the dynamics of metabolic systems using a novel model.
• To explore the role of carrier cycling cascades (CCC) in metabolic pathways.
• To analyze how conservation laws influence metabolic flux and feedback.

Main Methods:

• Proposed a carrier cycling cascade (CCC) model incorporating substrate and carrier dynamics.
• Analyzed the effects of conservation laws on flux and feedback within the CCC model.
• Investigated the robustness and responsiveness of the CCC model to environmental and internal fluctuations.

Main Results:

• Demonstrated that conservation laws induce flux jamming and feedback in metabolic systems.
• Showed that the CCC exhibits slow relaxation dynamics, distinct from elementary reaction timescales.
• The CCC model displays robustness against small environmental fluctuations and responsiveness to large changes.
• Identified key parameters conferring robustness against both external and internal fluctuations.

Conclusions:

• The CCC model provides a framework for understanding metabolic dynamics influenced by conserved quantities.
• Metabolic systems exhibit inherent robustness and responsiveness due to conserved moiety dynamics.
• Identified critical parameters for tuning metabolic system stability and adaptability.