Spectrophotometric determination of Fe transfer from L1 to DFO.

A complex of L1-Fe was formed by mixing Fe and NTA (5 mM FAS:35 mM NTA) with L1 to give final concentrations of 100 μM L1 and 10 μM Fe, followed by incubation for 1 hour at room temperature. A spectrum (range, 350-550 nm) of the L1-Fe complex was obtained (“L1-Fe complex”), followed by addition of 50 μM DFO to the cuvette, incubation for 10 minutes, and determination of a second spectrum (“L1-Fe complex + DFO”). The “DFO-Fe complex” was generated by mixing Fe and NTA (5 mM FAS:35 mM NTA) with DFO, to give final concentrations of 50 μM DFO and 10 μM Fe and incubating for 1 hour. The absorbance dip at 470 nm is due to instrument noise.