Metabolic system identification using simulation and fast Fourier transformation

A biological model of ketone body metabolism in the rat heart highlights pseudoketogenesis caused by reversible activation of acetoacetate. A mathematical system based on differential equations of isotopic fluxes is solved numerically. Different sets of unknown kinetic constants cannot be discriminated because of concentration patterns, but these patterns can be further analyzed. System poles are located by a fast Z-transform algorithm. The Z plane is scanned along constant damping contours, using an efficient fast Fourier transform algorithm. This simulation and Z-domain scanning approach reduce the need for subjective analysis of experimental data.<>