A deep and analytical understanding of the human metabolism grabbed attention of scientists from biology, medicine and pharmacy. Mathematical models of metabolic pathways offer several advances for this deep and analytical understanding due to their incompensable potential in predicting metabolic processes and anticipating appropriate interventions when required. This book concerns mathematical modelling analysis and simulation of metabolic pathways. These pathways include intracellular and extracellular compounds such as enzymes, metabolites, nucleotides and cofactors. The mathematical models are either in the form of nonlinear ordinary differential equations (ODE's) or differential algebraic equations (DAE's). These equations are composed of kinetic parameters such as kinetic rate constants, initial rates and concentrations of metabolites. In this book, an enzymatic system which includes Creatine Kinase, Hexokinase and Glucose 6-Phosphate Dehydrogenase (CK-HK-G6PDH) is modelled in the form of DAE's, solved numerically and the system parameters are estimated.