Figure 4. Double reciprocal plots of the arsenic methylation rate versus the concentration of SAM.

Reaction mixtures (100 µl) containing 11 µg enzymes, 1 µM iAs³⁺, 7 mM GSH in PBS (25 mM, pH 7.0) were incubated with different concentrations of SAM for 2 h with H₂O₂ treatment before analysis. Values are the averages ± S.D. of three independent experiments performed by three independently purified proteins.