Extended Data Fig. 9: Determination of Fe(II) concentrations by spectrophotometric measurements of the Fe(II)–ferrozine complex.
From: The Parkinson’s disease drug entacapone disrupts gut microbiome homeostasis via iron sequestration
The ferrozine reagent reacts with divalent Fe to form a stable magenta complex species with a maximum absorbance at 562 nm. a. Percentage of total Fe(II) in anaerobic solutions of FeSO4 containing increasing concentrations of Na2H2EDTA (a known Fe(II) chelator) or entacapone, as determined using the ferrozine method. b. Absorbance at 562 nm, indicating the presence of ferrozine-Fe(II) complexes in solutions of FeSO4 in degassed DMSO (100%) or degassed double distilled water, following reaction with increasing concentrations of ferrozine. c. Fe(II) concentrations in water or sM9 solutions of FeSO4 (1 mM FeSO4). FeSO4 was dissolved in degassed water or sM9 and incubated for 0, 1, 5, 10, 15 and 30 min, as indicated, before the ferrozine reagent was added. Concentrations of Fe(II) were determined using a calibration curve obtained by measuring absorbance at 562 nm in solutions of known Fe(II) concentration (see Methods) supplemented with 2 mM ferrozine. In a,b,c error bars denote standard deviation from triplicates per condition. Data are presented as mean values from three independent experiments +/- SD.
