1-deoxy-d-xylulose-5-phosphate and isopentenyl-pyrophosphate

A sensitive and versatile ion pair radio high-performance liquid chromatography (HPLC) method for the investigation of the deoxyxylulose phosphate (DXP) pathway has been developed, allowing the simultaneous separation of phosphorylated, nonphosphorylated, and nucleotide moieties bearing intermediates. Moreover, this method addresses the problem of separating the isomers isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP). Because the majority of the intermediates of this isoprenoid pathway lack a chromophore, the combination with an on-line radiodetector provides a highly sensitive tool for their detection. Chromoplasts isolated from Capsicum annuum and Narcissus pseudonarcissus served as model systems for the testing of the analytical procedures after the application of radiolabeled precursors. This HPLC system, which represents an improvement in analytical methods developed for the analysis of the mevalonic acid pathway, should be easily adaptable to other plant and bacterial systems and should permit further elucidation of the regulatory mechanisms that control the flow of intermediates through the DXP pathway and the coordination with related metabolic pathways. Moreover, the system can serve as an analytical tool in the screening for inhibitors of this pathway, allowing the development of new antibiotics as well as herbicides, because this pathway is absent in vertebrates.

Topics: Capsicum; Carbon-Carbon Double Bond Isomerases; Chromatography, High Pressure Liquid; Hemiterpenes; Isomerism; Narcissus; Organophosphorus Compounds; Plastids; Xylose