On the Biosynthesis of the Pigments of Penicillium islandicum. II.

Abstract

The acetate origin of islandicin from P. islandicum is shown by degradation after feeding the mold with C14-carboxyl-labelled acetate, resulting in a strict alternate labelling of the anthracen structure. By feeding the mold with O18-labelled acetate, 3 hydroxyl groups in islandicin and 4 in emodin are shown to be derived from the carbonyl group of acetic acid. Furthermore, the incorporation of O18 in the secondary alcoholic groups of rubroskyrin indicates their formation from keto groups, originating from acetate, by hydrogenation.