Figure 4.

Purified recombinant MtcB-dependent methylation of cob(I)alamin with l-carnitine. A, methylation was followed by the increase at 540 nm in the complete reaction (●) as described under “Experimental procedures.” Methylation was not observed in the absence of MtcB (▴) or l-carnitine (■). B, kinetic analysis of MtcB in which the l-carnitine concentration was varied at different set cob(I)alamin concentrations. The numbers beside each curve are the millimolar concentration of cob(I)amin used for that data set. Each point is the average of three determinations. Error bars, S.D. Some error bars are not visible due to size of data point markers.