. 2011 Mar 14;108(13):5402–5407. doi: 10.1073/pnas.1100410108

Table 1.

Properties of various Rpe metalloforms

Metal	k_cat (s⁻¹)	K_M (mM)	k_cat/K_M (M⁻¹ s⁻¹)	t_1/2 of metal dissociation
Fe ²⁺	67,000 ± 7,700	1.6 ± 0.2	4.2 × 10⁷	50 min
Mn ²⁺	30,400 ± 1,700	1.8 ± 0.1	1.7 × 10⁷	3.5 min
Co ²⁺	14,700 ± 900	2.4 ± 0.4	0.6 × 10⁷	20 h
Zn²⁺	1,300 ± 100	4.8 ± 0.5	0.02 × 10⁷	8 h

k_cat and K_M values were determined as described in Materials and Methods. Error represents SD from the mean of three independent measurements. Dissociation rates were determined by measuring the loss of Rpe activity during incubation of metal-loaded enzyme with an excess of the chelator DTPA at 23 °C. DTPA was shown to trap dissociated metals but not to extract them actively (SI Materials and Methods). Measurements represent the averages of three independent experiments.