TABLE 2.
Iron content of S. pneumoniae and E. coli
| Strain | Mean total iron contenta (ng/mg of protein) ± SD | Concn (μM)b of: |
||
|---|---|---|---|---|
| Fe3+ | Fe3+ with DF | Fe2+ (free iron) | ||
| S. pneumoniae R6x | 911 ± 11 | 40 | 268 | 228 |
| E. coli AB1157 | 760 ± 8 | 30 | 170 | 140 |
a
Total iron content was determined in washed cells by inductively coupled plasma-optical emission spectroscopy. Values are the averages of five determinations.
b
Free iron was assayed in intact, washed cells using electron paramagnetic resonance and normalized based on intracellular protein content. All concentration values are the average of seven scans and are representative of three independent determinations.