Abstract
The metabolic flux of two phenylpropanoid metabolites, N-p-coumaroyloctopamine (p-CO) and chlorogenic acid (CGA), in the wound-healing potato tuber tissue was quantitatively analyzed by a method based upon the tracer experiment using stable isotope-labelled compounds and LC-MS. Tuber disks were treated with aqueous solution of L-phenylalanine-d5, and the change in the ratio of stable isotope-labelled compound to non-labelled (isotope abundance) was monitored for p-CO and CGA in the tissue extract by LC-MS. The time-dependent change in the isotope abundance of each metabolite was fitted to an equation that was derived from the formation and conversion kinetics of each compound. Good correlations were obtained between the observed and calculated isotope abundances for both p-CO and CGA. The biosynthetic flux of p-CO and CGA were determined 1.15 and 4.63 nmol / g fw / h, respectively.
