Upgrade and repair of high performance liquid chromatography

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Isoprenoids are the largest class of natural products with more than 70,000 known structures. Despite their structural complexities, all isoprenoids are biosynthesized by a simple building block, five-carbon isopentenyl diphosphate (IPP). As many isoprenoids have direct implications in human society as pharmaceuticals, nutraceuticals, flavors, and polymers, how this simple IPP can be transformed to a diverse array of isoprenoids has been intensively studied. My research program focuses on elucidating biochemical mechanisms for the formations of diverse isoprenoids with an aim at providing knowledge for biotechnological productions of naturally scarce isoprenoids. Two major isoprenoids of interest in my laboratory are the biopolymer of natural rubber and pharmaceutically important sesquiterpene lactones. Natural rubber is a poly-cis-isoprene biopolymer, comprised of more than a thousand IPP monomers. Despite progresses in polymer chemistry, synthetic rubber derived from petroleum cannot fully replace natural rubber in manufacturing industries because the physical properties of synthetic rubber cannot surpass those of natural rubber (e.g., elasticity, heat dissipation, and abrasion resistance). Natural rubber is, therefore, an irreplaceable biomaterial synthesized from plant. On the other hand, sesquiterpene lactones form an important group of small isoprenoids, members of which have been used as anti-malarial (e.g., artemisinin) and anti-prostate cancer (e.g., thapsigargin) drug. However, most sesquiterpene lactones are present at low quantities in nature and their chemical synthesis is economically not viable due to their stereochemical complexities. The enzymatic synthesis of sesquiterpene lactones in surrogate hosts has emerged as an alternative biological production. However, the biochemical mechanism of how these isoprenoids are synthesized remains elusive, limiting biotechnological productions of these compounds. My research has identified a novel protein complex necessary for natural rubber biosynthesis, using lettuce as a model system. We have also elucidated a complete biosynthetic pathway of the simplest sesquiterpene lactone, costunolide. Advancing the biochemical knowledge for natural rubber and sesquiterpene lactone has been dependant on the routine use of an analytical instrument, high performance liquid chromatography (HPLC) coupled with a photodiode array detector (for sesquiterpene lactone analysis) and an evaporative light scattering detector (for natural rubber analysis). Reliable detection, quantitation, and purification of small or polymeric isoprenoids using HPLC are essential analytical practices. Timely upgrade and repair of HPLC are critically required to continue the metabolic studies of the isoprenoids.