Über die Biogenese des Rifamycins S

Abstract

Abstract Propionic acids labelled either with 14 C in positions 1, 2, or 3, or with 14 C in position 1 and 3 H in position 3 have been used as precursors in biosynthesis of rifamycins by Streptomyces mediterranei . The resulting distribution of radioactivity in rifamycins S – as determined by systematic degradation – shows that 23 of the 37 carbon atoms in rifamycin S originate from propionic acid. This result and the distribution pattern of radioactivity are in agreement with those obtained recently by 13 C‐NMR. spectroscopy [7]. The S‐methyl groups of methionin, labelled with 14 C, are incorporated in rifamycins by Streptomyces mediterranei only in the methoxy group. The consequences of these findings for the biogenesis of other ansamycins, e.g . streptovaricins, are discussed. The similarities in the constitution and configuration of ansamycins and macrolides ( cf . [9]) indicate that all these microbial metabolites are formed according to the same biogenetic pattern.