Biosynthesis of arglecin and related compounds

The requirements for maximum production of arglecin, 3-isobutyl-6-(3-guanidinopropyl)-2(1H)pyrazinone, by Streptomyces toxytricini grown on either yeast extract or synthetic medium, were supplements of L-arginine and L-leucine. The arglecin produced was derived to a major extent from these amino acids, as was shown by comparison of specific activities in 14C-labeling experiments.Various compounds related to arglecin could be synthesized by the organism, and these were isolated and their structures determined primarily by natural-abundance carbon-13 and proton magnetic resonance methods. In old cultures which had produced arglecin, the metabolite 3-isobutyl-6-(3-aminopropyl)-2(1H)pyrazinone was found. In cultures grown on synthetic medium supplemented with L-leucine and L-homoarginine, the metabolite 3-isobutyl-6-(4-guanidinobutyl)-2(1H)pyrazinone was found, and in cultures that had been supplemented with L-norleucine and L-arginine, the metabolite 3-butyl-6-(3-guanidinopropyl)-2(1H)pyrazinone was found.