FIG. 3.

RP-HPLC analysis of enterobactin and its degradation products synthesized from several E. coli strains. Enterobactin and its degradation products were extracted from acidified supernatants from cultures of derivatives of E. coli strain GG199 (Δfur::cat), with additional deletion of the indicated genes, grown overnight in minimal medium at 37°C for 16 h, and subjected to HPLC analysis. Shown are panels of individual chromatograms. Peaks of enterobactin (E) and its degradation products DHBS triester (T), DHBS diester (D), and DHBS (M), tryptophan (W), and the injection peak (S) from the standard are indicated. Values of a medium control were subtracted from all chromatograms. The concentration profile of the gradient of acetonitrile is indicated.