Table 1

Comparison of model FeL complex formation and dissociation rate constants, conditional stability constants, and Fe' and Fe3+residence times in treated with Chelex, photo-irradiated seawater as determined using the kinetic method. Errors represent average mean ± s (standard deviation) from two separate replicates.[1] Data taken from ref. 12

Model ligand
kf × 105/M-1s-1
kd × 10-6/s-1
log KFe'L kinetic
log KFe 3+ L kinetic
Fe' residence time/yr
Fe3+ residence time/yr
log Ktherm

Protoporphyrin IXa
6.2 ± 0.8
0.7 ± 0.7
11.9 ± 0.5
21.9 ± 0.5
0.031
645
--
Protoporphyrin IX Dimethyl estera
15.3 ± 0.2
0.2 ± 0.9
13.0 ± 0.2
23.0 ± 0.2
0.116
5866
--
Phaeophytina
12.2 ± 0.1
12.3 ± 16.8
11.0 ± 1.2
21.0 ± 1.2
0.002
72
--
Apoferritinb
0.93 ± 0.3
0.08 ± 0.04
12.1 ± 0.1
22.1 ± 0.1
0.275
820
--
Phytic acidc
12.8 ± 0.1
0.51 ± 0.28
12.4 ± 0.2
22.4 ± 0.2
0.043
1820
--
Alterobactin Ad
3.8 ± 0.8
0.17 ± 0.04
12.3 ± 0.4
22.3 ± 0.4
0.129
1620
49–5318
Alterobactin Be
8.0 ± 0.6
0.25 ± 0.02
12.5 ± 0.3
22.5 ± 0.3
0.088
2330
43.648
Enterobactin1f
10
15.8
10.8
20.8
0.013
46.0
49.020
Ferrichromeg
4.6 ± 2.9
0.05 ± 0.04
12.9 ± 0.1
22.9 ± 0.1
0.439
6700
29.0731
Desferrioxamineg
19.6 ± 10.1
1.5 ± 1.8
12.1 ± 0.6
22.1 ± 0.6
0.015
952
30.6031

Fe complexing moieties for the model ligands: aPorphyrin. bProtein. cPhosphate. dβ-Hydroxyaspartate/catecholate. eBis-catecholate. fTris-cate-cholate. gtris-Hydroxamate.

Luther et al. Geochemical Transactions 2001 2:65   doi:10.1186/1467-4866-2-65