The Biosynthesis of Indolmycin

Indolmycin, an antibiotic produced by a strain of Streptomycesgriseus, is formed from (S)-tryptophan, which loses from its side chain the amino nitrogen atom, the hydrogen atom from C-2, and one of the hydrogen atoms from C-3, two intact methyl groups of (β-methionine, and the guanido carbon atom of (S)-arginine. (R)-β-Methylindolepyruvate and (2S,3R)-indolmycenic acid are intermediates in the biosynthesis. The absolute configuration of indolmycin has been determined by chemical correlation with (-)-(R)-indoleisopropionic acid. Studies with cell-free extracts of 5. griseus revealed the presence of a transaminase which converts (S)-tryptophan into indolepyruvate and a methyltransferase which C-methylates indolepyruvate.