Biosynthesis of Violacein: Origins of Hydrogen, Nitrogen and Oxygen Atoms in the 2-Pyrrolidone Nucleus

Abstract

The biosynthetic origins of the hydrogen, nitrogen and oxygen atoms in the pyrrolidone ring of violacein were established by an anaylses of the 1H, 13C NMR and MS spectra of its isotope-enriched metabolites. Feeding experiments of [2-2H] and [3-2H2]tryptophans have revealed that the hydrogen in the pyrrolidone ring was derived from the methylene protons at the 3-position of tryptophan. The stereochemical fate of the prochiral hydrogens was determined to be in the retention of the pro-S hydrogen by these feeding experiments using and [3S-2H]tryptophans. The incorporation experiment of [a-15N]tryptophan demonstrated that the nitrogen atom in the ring originated from the a-amino group of tryptophan. The incorporation experiment of 1802 gas verified that all the oxygen atoms of violacein were derived from the molecular oxygen. © 1987, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.