Petri Net-Based Framework for Oxygen-Sensitive Regulation of Pyruvate Metabolism in M. tuberculosis

Pyruvate serves as a central hub of cellular metabolism, linking glycolysis with downstream pathways such as the tricarboxylic acid (TCA) cycle, gluconeogenesis, and fermentation. Its metabolic flexibility enables organisms to switch between oxidative and fermentative fates depending on oxygen availability and environmental stress. In this study, a Petri net (PN) model of pyruvate metabolism in Mycobacterium tuberculosis H37Rv was developed to capture and simulate these dynamic transitions. Using Snoopy 2.0 for model construction and COPASI for simulation, the framework incorporated key metabolites, cofactors, and enzymatic processes regulating aerobic and anaerobic states. The model demonstrated that oxygen availability acts as a regulatory switch, channeling pyruvate either toward acetyl-CoA for ATP generation under aerobic conditions or toward lactate production under hypoxia to regenerate NAD+. Structural validation confirmed boundedness, conservativeness, and deadlock-free behavior, underscoring the robustness of the framework. Sensitivity analyses highlighted enzymatic kinetics as critical determinants of flux distribution and system stability. Collectively, the PN model provides a scalable and biologically relevant computational framework for exploring oxygen-dependent metabolic reprogramming, offering insights into energy adaptation and potential therapeutic targets in pathogenic systems.