The biosynthesis of phenazines: incorporation of [14C]shikimic acid

Abstract

Specific and self-consistent incorporations of [1-¹⁴C]-, [6-¹⁴C]-, and [1,6,7-¹⁴C₃]-shikimic acid into iodinin in Brevibacterium iodinum closely define the orientation of the precursor molecule in the phenazine metabolite. [1,6,7-¹⁴C₃]Shikimic acid gave phenazine-1-carboxylic acid with one fifth of the activity in the carboxy-group, which requires the involvement of two precursor molecules in biosynthesis or incorporation via a symmetrical intermediate derived from only one precursor molecule. Neither [³H]anthranilic acid nor [¹⁴C]dihydrohydroxyanthranilic acid was significantly incorporated into iodinin. Decarboxylation of [ring-¹⁴C]pyrazinetetracarboxylic acid under various conditions has been studied; with copper chromite, but not with copper–bipyridyl–quinoline, radioactivity (up to 12%) appeared in the liberated carbon dioxide.