Table 1.

Millimolar concentrations of urea increase the initial rates of Fe²⁺-bipyridyl formation from ferritin, triggered by the addition of NADH/FMN to ferritin

Urea, mol⋅L−1	Protein	Initial rate, μmol⋅liter−1⋅s−1 (pH 7.0)
0	WT	0.890  ± 0.063
0.001	WT	1.920  ± 0.088
0.010	WT	2.608  ± 0.246
1	WT	4.848  ± 0.331
2	WT	1.272  ± 0.352
0	H-L134P	3.778  ± 0.410

Recombinant ferritin (2.06 μM mineralized with 480 Fe, added as FeSO₄ in air) was mixed with an equal volume of NADH, FMN, and chelator each at 5.0 mM as described (3). Initial rates were determined from linear fits (0–2 min) as described in Experimental Methods. The data are means for two to three independent protein preparations with the error as the standard deviation.