Two Tropinone Reductases, That Catalyze Opposite Stereospecific Reductions in Tropane Alkaloid Biosynthesis, Are Localized in Plant Root with Different Cell-Specific Patterns

概要

論文の詳細を見る
In the plant species that produce tropane alkaloids, two tropinone reductases (TRs) catalyze the stereospecific reductions of the 3-carbonyl group of tropinone. This reduction is a key branch point that determines the metabolite flow into the separate alkaloid groups, eacn with different stereospecific configurations. In this study, a specific antibody was prepared for each of the TRs by immumizing mice with recombinant TR protein and subsequent immuno-affinity purification of the antiserum. Immunoblot analyses revealed that accumulation of both TRs was highest in the lateral roots of Hyoscyamus niger throughout its development. In cultured roots, TR proteins were accumulated in a basal region but not in root apex. These patterns were similar to that of hyoscyamine 6β-hydroxylase (H6H), an enzyme that catalyzes a downstream step in the same biosynthetic pathway. However, an immunohistochemical analysis revealed that the two TRs and H6H were accumulated with different cell-specific patterns in the cultured root, suggesting transportation of the alkaloid intermediate(s) across the different cell layers.
日本植物生理学会の論文