Kinetic constants for different Ohr substrates.

Peroxidase assays were performed as described in Materials and Methods with the concentrations of all components except the peroxides (eight concentrations; 0–1 mM) held constant. To determine Michaelis constants, all reaction mixtures contained 50 mM sodium phosphate (pH 7.4), 50 mM NaCl, 1 mM DTPA (pH 7.4), 0.2 mM NADPH, 0.1 μM Ohr, and either the Lpd/SucB system (5 μM SucB and 40 μM Lpd), the LpdA system (40 μM), or the Trx system (5 μM TrxR and 40 μM Trx). The data represent the means obtained from three independent assays.Kinetic constants for different Ohr substrates.