RT Journal Article SR Electronic(1) A1 Troost, Thomas A1 Katz, EdwardYR 1979 T1 Phenoxazinone Biosynthesis: Accumulation of a Precursor, 4-Methyl-3-hydroxyanthranilic Acid, by Mutants of Streptomyces parvulus JF Microbiology, VO 111 IS 1 SP 121 OP 132 DO https://doi.org/10.1099/00221287-111-1-121 PB Microbiology Society, SN 1465-2080, AB Mutants of Streptomyces parvulus that are blocked in the synthesis of the phenoxazinone-containing antibiotic, actinomycin, were isolated by the ‘agar piece’ method (after ultra-violet irradiation or treatment with 8-methoxypsoralen plus near-ultraviolet light). Radio-labelling experiments in conjunction with paper, thin-layer and column chromatography revealed that 4-methyl-3-hydroxyanthranilic acid (MHA) is a major metabolite accumulated by these mutants. Studies in vitro and in vivo provided evidence that MHA is a precursor of the phenoxazinone chromophore, actinocin. Normally MHA does not accumulate during growth or antibiotic synthesis by the parental strains. Protoplasts derived from the mutant strain AM5 synthesized MHA in significant amounts. A scheme is proposed for the biosynthesis of actinomycin D that accounts for the accumulation of MHA by the mutants., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-111-1-121