Fig. 5.

FzmO converts glutamylacetylhydrazine (5) to glutamylhydrazine (6). All samples were derivatized with Fmoc-Cl, and the mass of Fmoc-derivatized 6 ([M+H]⁺ = 384) was monitored by LC-MS. a Deacetylation of 5 to 6 by FzmO in vitro. b Extracted ion chromatogram (EIC) for m/z  384 of the reaction containing FzmO and 5. c EIC for m/z = 384 of a sample containing 5 without FzmO. d EIC for m/z  384 of a synthetic standard of Fmoc-6. e EIC for m/z  384 of a synthetic standard of Fmoc-6 spiked into the reaction mixture containing FzmO and 5 in panel b. f EIC for m/z  368 of Fmoc-derivatized Glu standard. g EIC for m/z 368 of the reaction mixture of FzmO and glutamylacetylhydrazine. h HRMS analysis of ¹⁴N incorporation into ¹⁵N-labeled fosfazinomycin A in Streptomyces sp. NRRL S-149 fed with unlabeled 6. The calculated m/z ([M+H]⁺) for ¹⁵N-fosfazinomycin A containing two ¹⁴N atoms is 459.2025. i HRMS analysis of ¹⁵N incorporation into kinamycin D from feeding 0.2 mM of ¹⁵N₂-6 to cultures of S. murayamaensis. ¹⁵N₂-kinamycin D ([M+H]⁺ = 457.1026)