Modeling metabolic processes between molecular and systems biology

Currently, there are two main 'schools' to handle the complexity of a living cell, the molecular biological paradigm that for each cellular function there is a key enzyme, and the complementary systems biological view that function emerges from the connectivity of the many enzymes. Here I argue that a combined molecular-systemic modeling ansatz would combine the strengths of both concepts and allow to build models that are detailed on the local level, reflect the high connectivity of cellular metabolism, and are still manageable. An overview over recent modeling advances shows that the tools and techniques are available for a hierarchic setup of even large systems form local rules which are then suited for a systemic analysis and parameterization.