The rate of turnover in a metabolic pathway, otherwise known as the metabolic flux , is regulated based on the stoichiometric reaction model, the utilization rate of metabolites, and the translocation pace of molecules across the lipid bilayer .  The regulation methods are based on experiments involving 13C-labeling , which is then analyzed by Nuclear Magnetic Resonance (NMR) or gas chromatography-mass spectrometry (GC-MS) -derived mass compositions. The aforementioned techniques synthesize a statistical interpretation of mass distribution in proteinogenic amino acids to the catalytic activities of enzymes in a cell. 
Targeted gene deletions, mutagenesis screens and a genome-scale RNA interference (RNAi) screen have identified approximately 300 gene inactivations that cause fat reduction and approximately 100 gene inactivations that cause fat accumulation without significant effects on growth and viability ( Ashrafi et al., 2003 ; Jia et al., 2004 ; Kniazeva et al., 2004 ; Kniazeva et al., 2003 ; Ludewig et al., 2004 ; Mak et al., 2006 ; McKay et al., 2003 ; Mukhopadhyay et al., 2005 ; Taubert et al., 2006 ; Van Gilst et al., 2005 ; Vellai et al., 2003 ; Watts and Browse, 2002 ; Yang et al., 2006 ). Another approximately 250 gene inactivations cause dramatic fat reductions concomitant with defects ranging from sterility to growth arrest and lethality. Because of these pleiotropies, it is difficult to assign specific fat regulatory functions to such genes although they include some well-known components of metabolism.