Initial rates of oxygen consumption by MTOX measured at various oxygen and sarcosine concentrations in 0.1 M ACES, 52 mM Tris, 52 mM ethanolamine-HCl, and 1 M KCl at pH 9.4 and 25 °C. The lines are from fits of the data to eq 2. The sarcosine concentrations were 18.5 mM (■), 46.3 mM (△), 92.6 mM (●), 185 mM (○), and 278 mM (●).