Single-substrate Enzyme Kinetics: The Quasi-steady-state Approximation   and Beyond
  We analyze the standard model of enzyme-catalyzed reactions at various substrate-enzyme ratios to identify the regions of validity of the quasi-steady-state approximation. Certain prevalent conditions are checked and compared against the actual findings. Efficacies of a few other measures are highlighted. Some very recent observations are rationalized, particularly at moderate and high enzyme concentrations. 
Sharmistha Dhatt and Kamal Bhattacharyya
physics.chem-ph