FIG 2.

MtpA does not catalyze methylcob(III)alamin:CoM methyl transfer reaction. (A) MtpA-catalyzed methylcob(III)alamin:MPA methyltransferase activity monitored by UV-visible spectroscopy. The reaction being monitored is shown to the right of the plot. (B) A similar assay attempting to show MtpA-catalyzed methylcob(III)alamin:CoM methyltransferase activity. No activity was observed within the 12-h assay. Reactions were initiated by addition of MPA (A) or CoM (B) at 150 μM as indicated by the arrows.